Hello Andrew,
I have a Yamaha S08 that I use with Composer with much success and another forum member uses a Yamaha Tyros. My S08 connects via USB to a laptop that I position on top of the keyboard in an unobtrusive area void of any switchs. I can view the screen easily. I've downloaded a cakewalk .ins (instrument definition file) and imported it into Composer, it works pretty well. My S08 also came with Yamaha's SQ01 sequencer program, I switch between Composer and SQ01 to record myself. Your Motif looks like a pretty serious instrument.

Regards
Larry S