Expander die question

[Mr. 16 gauge]

I'd like to try shooting some cast bullets in my .35 Remington Marlin 336; however, I'm put off a bit by the fact that I've heard conflicting stories about the 'microgroove' rifling not shooting cast bullets well. I really don't want to invest the time & money in buying molds, handles, ect. and then finding it was all for naught.
I did find a company that supplies cast bullets, and one of them is the 200 grain RCBS flat nose 200 grain GC bullet for the .35 Rem. I'm thinking about buying a box of these and trying them before I put out an investment in the molds.
I reload cast bullets for my .30/30, and found that in order to get any accuracy, I had to get a die that flares the case mouth a bit.....no big deal. Before I buy such a thing for the .35, I'm wondering if I can use the expander die from my .357 magnum dies to expand the mouth on the .35 Remington cases enough to load the cast bullets......what do you all think?