If the custom is from one of the smiths that sponsor here, any of them, you can be sure that you are getting the best of the best.
I've only dealt with one smith here and him only twice. The major reason for only two is I waited too late in life to experience full appreciation of a fully custom rifle.
A 1 MOA guarantee is now pretty much impossible to accept.
I notice that Shawn seems to almost require a half moa rifle for his extreme distance shooting classes.
Kirby, Nate, Jim, Shawn , tmr, are just a few of the names to check out. There are others others. They can shoot me for not having their names on the tip of my fingers.
Of the smiths here, I'd choose, especially at my age, the one with the shortest delivery time.
My carry gun is a Remmy 700 338 RUM, tuperware stock, Holland QD brake. It is a DIY rig and looks it. Shoots with the customs though.
The two ambush rigs are both APS built. One is one of the first 270 AMs the other is a recent 375 AM. The APS rifles can share my bed. The DIY rifle stays on the floor.