Dye should not run off on clothing...are you sealing it with a finish? You line up 6 guys, and you'll hear 6 ways to finish leather. I have used Doc Baileys Leather Tonic for several years now and I'm sticking to that.
I've heard guys using coffee, boiling walnuts, etc.....talk about messy. Seems like a lot of work, when Feibings is sitting on the shelf waiting to be used.
As long as you're experimenting, let us know how Rit works out...but in my view, Feibings has done all the experimenting for us.