Right up front, you won't be able to shoot very hot loads in the Marlin due to the spring of the action with the rear lockup. That said, using lead loads with a medium crimp should work well. Until you actually try lead loads in the "micro groove" barrel you won't know if your barrel will tolerate them. I was lucky loading for a .444 a few years ago using 300 grain LFN pills, it shot them well out to 100 yards with minimal leading. A very hard cast bullet should shoot as well as any jacketed bullet in that barrel. Your lube shoudn't cause any problems.

Tom