My 2 cents...
I have a pair of custom molded plugs that were fitted many ears ago.

But seriously folks, They did work well but after a while they did not seem to fit as well as when they were new.
I read somewhere that the human ear grows or changes as you get older. This makes sense as I sure don't look the same as I did 30 years ago.
Therefore be warned that custom fit ear plugs are not forever.
And while on the subject of ear protection, I just picked up a set of "Howard Leight" electronic ear muffs model# R-01902. ($63.00 on Amazon)
I have owned other electronic muffs before and the cheaper units kill all the sound when shot are fired so you cannot hear someone talking to you.
The electronics in these muffs supress the shots while allowing other sounds (like speech) to pass.
But the thing that really impressed me about these particular muffs was the engineering and thought that went into them. They are well built, comfortable and easy to use.They also have a very high natural NRR. So they really block out loud booms.
The only negative is that they are large (thus the high NRR) so I don;t think they are suitable for rifle shooting. I shoot mostly pistol so it was not my concern.