Smooth sizing works fine but keep your barrel drop anyway. I would go 1-20 Brux...his standard Savage Prefit. You wont gain anything from the 1-18 unless you want to shoot long 350gr+ and most people dont.

BTW make sure you have a 4.40 spacing and large shank barrel. You will have WAY less stock options in the 4.27 spacing. A Savage large shank is still smaller than a Rem700 at the shank and if you have any desire to shoot the upper end loads its a safer way to go