I generally cut off the thumb and the index finger at the first joint.
Not sure about eyeeatingfish, but I have 2 trigger fingers and he may also.  How many do you have?

To me, it more depends on why I'm wearing gloves.  For warmth in extreme cold or to prevent fingerprinting, I'd obviously want all my fingers covered. 

If you only need them to protect against cuts and scrapes, padding to ease recoil, and to increase grip friction preventing slipping, then I'd buy fingerless gloves to start with.  No sense in ruining a new pair if you might need a complete glove later.

Your mileage may vary.

To me, it more depends on why I'm wearing gloves.  For warmth in extreme cold or to prevent fingerprinting, I'd obviously want all my fingers covered. 

If you only need them to protect against cuts and scrapes, padding to ease recoil, and to increase grip friction preventing slipping, then I'd buy fingerless gloves to start with.  No sense in ruining a new pair if you might need a complete glove later.

Your mileage may vary.

My mileage definitely varies.  FWIW, I have been wearing gloves on a regular basis, almost daily professionally for a long time.  I know what works for me and the reasons for it.  I don't want want a set of complete fingerless gloves.  If I am shooting in cold weather which is not so common, I do have more than one set, but when it comes to the Glock, which is what i mostly carry, they are not the best.

I generally cut off the thumb and the index finger at the first joint.
Not sure about eyeeatingfish, but I have 2 trigger fingers and he may also.  How many do you have?

Can I ask if that is just personal preference or is that based off of any combat experience?

I normally don't wear gloves while shooting, however I recently bought some on a recent trip to the mainland.
I planned on wearing them for HDF shoots, I haven't done that yet. I did shot a M9 qual range with them and they were fine while shooting but not being used to wearing gloves and not modifying them by cutting fingers I noticed a significant loss of dexterity in removing rounds from the box and loading my mags.

I like the gloves they seem to be well made and cleaned up good after a trip in the washer. They are not very thick on the inside and the back is a breathable mesh.

On Amazon: Robinson Outdoor Products Whitewater Foliage Stretch Shooting Glove, Foliage, X-Large https://www.amazon.com/dp/B00V8IFP08/ref=cm_sw_r_cp_awd_4peEwbC3FE38Z

Company's website: www.whitewateroutdoors.com

I also have two primary trigger fingers r/l and a few other fingers and thumbs that could be used if needed. Seriously I try and shoot both handed a often as possible usually switching hands after each mag.

Can I ask if that is just personal preference or is that based off of any combat experience?

I am not in the military nor have I been.  I have been fortunate enough to have attended a few military schools and I do train with or provide training to certain members / units within the military currently.

As for gloves, my concerns while working are for protection against glass, flash or general cuts / scrapes.  Heat is really only an issue when training, but a very valid issue when running certain weapons hard.  As for the fingers and thumb removal, I want as much coverage as possible however I prefer the tactile feel of safeties, slide stops, bolt releases and yes trigger manipulation, however pulling the trigger is less of a concern.  When it comes to triggers, I carry a Glock daily and the small size of the trigger guard and clearances are not the most ideal when it comes to gloves.  When running pistols (pistol dependent) I prefer the slide stop or slide catch to release the slide.  I have a much more positive and reliable manipulation of weapons with these 2 fingers of the gloves being removed at the middle joint.  I am fairly ambidextrous with a rifle or pistol so obviously I do opt to remove these fingers from both gloves.  In cold weather I will generally run full finger gloves, but that is not the environment that I am normally working within.  I will however note that I train quite frequently without gloves.

The comment about the modern space guns was tongue-n-cheek as I carry one professionally and I do a lot of smithing and armoring on this system, in addition I also build/assemble them on a regular basis.  My curriculum for a carbine course is heavily based on the M16/M4/AR15 category of rifles, so I do very much like the platform.  I will also note that my employer provides my gloves, however I have several pairs that I have on my own and the Mechanix gloves are only the latest gloves that I have acquired on my own and I have been pleased with them.

I will also add that glove choice or even the desire to wear them is very much a user preference when you don't need to keep your hands warm.  So I will also echo what was mentioned above in the user's mileage may vary.  Gear and guns are cool, but many may have not quite worked all the small details when it comes to gear or weapons.  That is OK as it is a learning process, but ultimately have a good reason for choosing what you choose, be it guns, gear, etc.. There is nothing wrong with enhancing your situation as it pertains to you provided it is sound and does have added value, not just a perceived benefit.  So indeed my mileage may vary here from someone else, but their uses or experiences may differ from mine and vise versa.

I guess the end result like anything else boils down to a matter of preference. That being said where is the best place to purchase a set of mechanix gloves?

I've had good results with Mechanix and Camelbak (from Mojo).  I have some fairly thin ones for warmer climate and more thicker (probably the "standard" thickness) for colder weather.  I've shot in temps down into the teens in snow and the standard thickness Camelbak and Mechanix gloves were warm enough as long as they were dry.  Once they got wet, they weren't much help warmth wise.  My last class in Alaska, I had multiple pairs of gloves to use. 

Heat of the barrel isn't much of a concern to me in terms of gloves.  Well, maybe with my AK, but I rarely shoot that gun.  After shooting say 60 rounds at an ok pace, my handguard got hot enough that it was painful to handle with bare hands. 

Soooo............back from a pistol class in Texas this month.  Ran between running gloves, Mechanix, and Pig gloves. 

Running gloves worked decently but for the weather it was really too cold.  So I nixed those, also believe it or not my dexterity was better with the Mechanix and Pigs.

Mechanix worked well, but fitment was not as good as I had hoped (and this was my set).

Pig gloves I used were from a friend and fit better than the Mechanix.  Dexterity was as good or slightly better than the Mechanix for me.  Also the material was thick enough it provided that little better edge than the thin (Under Armor) running gloves and the Mechanix too.  So............I told my friend the Pig gloves were crap and am not giving them back to him because they suck..............  :p