I just finished this build. The specs are;
Remington 788, the original barrel was a .223
Douglas 1-11 twist barrel chambered in a Todd Kindler 20 VarTarg dimensioned for Lapua brass (221 Fireball)
Timney 1.5 lb. Trigger
Boyd Stock (second grade from eBay)
Cerakote Vortex Bronze and Micro Slick on the bolt
I polished the striker and replaced the sticker spring.
Trued the receiver face and had my local machine shop surface grind the recoil lug.
Next steps, develop a load. I have 32 gr V-Max and 35 gr Berger FB Varmint Bullets and AA2200, N120, and H335 powder to work with.
Questions and comments welcomed.