For all out flexibiliy...go with the 30-30 as it has the easiest to find factory ammo. It would be my #1 choice of the two you have mentioned. The .35R is a wonderful round but factory ammo can be tempermental as far as firing in some barrels that I've tried...it a headspace issue w/ the smallish shoulder and non-rimmed case head. You also have the 375JDJ so there is no real need for a .35 caliber cartridge.

Gary mentioned the Waters...great cartridge if you handload. Factory ammo is scarse.