Creating a homemade mix is extremely tedious and complex, it's not for just anyone. I know members like Cypher create their own homemade mixes, so contacting someone like them directly would be a good option if you really want a homemade food.
As for your question on species specific mixes,
Syrians and robos can be fed on the same diet. Any nutritionally complete diet is suitable for them as neither species is prone to diabetes
Russians and Chinese hamsters should be fed on a diabetes friendly diet only. Burgess dwarf is best for this purpose
Good luck
