Your primary problem, with an S900, is that the MIDI to transmit style parts (I presume you wanted to improve the style parts as well as just the RH voices seeing as how that is probably 80%+ of what anyone is hearing) is pretty primitive.

If I remember right (correct me if I'm not), the style section is an 'all or nothing' affair. You can't select just a few parts to transmit, and some to remain Internal.

Before you make this purchase, you need to investigate the S900's manual VERY carefully...