If that bullet is similar to the 124 xtp try the dimensions for the 124 xtp as related in the xtp project thread.
Sadly, that thread is so old the pictures aren't there any more.
https://2ahawaii.com/index.php?topic=7656.0I would run CFE pistol around 5.5 gr. based on testing from the gold dot project.
About 33 years ago I tested Hornady 115 gr.JHP bullets with HP38 powder but that powder is not good for this purpose because it burns too fast.
CFE is a modern powder perfect for this cartridge.
In the past I've tested 115 gr JHP from precision delta with AA7, Herco, Unique, HS6, HP38, 231.
The precision delta bullet is very similar in profile to the xtp bullets that I've seen...A truncated cone shape, right?
The most gratifying load I found was using a compressed load of herco. It gave me whopping speed and great accuracy.

Unique was similar.

Of course, the best thing to do would be to obtain a few rounds of factory ammo and dissect it and chrono the thing.
You got any? I do not.