Cast bullets & rifles: getting started...

[Mr. 16 gauge]

I already reload cast bullets in my .30/30 Winchester, but I had specific load data for those bullets. I would like to reload cast bullets in my .35 Remington, but can't find any specific data related to the RCBS 200 grain RNGC bullet. Can I use jacketed bullet data for this weight and start with the lowest loads listed? I plan on buying some of these bullets already cast; if they work out, I'll dish out the funds for the mold.
Thanks in advance.........