If I was going to build a 35 Whelan and intended to shoot 250 to 310 gr. bullets I would opt for the 1x16..If you want a 9.3x62 your locked in to a 1x16 as that is the standard and all there is out there...That twist has suited me perfectly in both calibers..

I also push the 9.3x62 pretty darn fast and get great accuracy..In fact I have a Brno Mod 21 in 9.3x62 for sale in the classified as we speak, it has a 1x16 Lothar Walthar barrel and it shoots 250 to 320s inside an inch...