Dr. Diff 10 x 2 1/2 inch or 11 x 2 1/2 rear drum brake Assy

Changing the SBP rear axles on my 68 GTS to BBP
what should I go with , 10 x 2 1/2 inch or 11 x 2 1/2 drums(Dr. diff) ?
Also. are screw in studs a better choice than the press in ?

Thanks