This business of proofing after screw cut for resale, genuine question, is this just if you sell it into the trade? Plenty of rifles get sold face to face privately and I bet I'm not alone in never having checked if they are in proof. Also, come to think of it, I've had rifles screw cut and traded them into to the trade and never had any questions asked about proof..... Just don't really see how this can be policed or enforced as a rule.
Personally, get that BSA cut and enjoy it, for the money you won't go wrong,Mand have plenty left over for everything else, possibly including a paid stalk or two for some guidance?