Scott. Regarding the right hand splits. I have a number of regular used registration setups with 2 sets of right voices (1 split) and I can still contain the left hand voice with the ACC's.
Another example the tune LOCOMOTION. I move the left hand voice (Brass Stabs) up into lower right hand in addition to 2 more separate right hand voice sections. this give 3 separate right voices. This is where the 76 keys come in.
I play a Tyros every week but the 9000Pro's key feel and response is for me far superior. Its all a matter of adapting to ones requirements. If I were to make a change at this time I would have a PSR2100 + PSR 292 as lower keyboard midi to trigger 2100 ACC & lower voice. I have seen this setup and its very infectious.

Graham UK