IIRC, the marlin handgun-caliber leverguns have a very slow twist rate; 1:38 iirc. May be wrong on that and it also may not be true of guns that age, but if it's true I'd base my starting point there - finding out what .35-caliber bullet weights can that twist rate effectively stabilize. I guess that would actually be the second thing, not the first thing.
First thing (if it were me) would be confirming the twist rate; and then checking into bullet weight options based on the twist rate you find.