I use One Man Band. I am not sure whether it's the best, because it's been so long since I tried Live Styler or the other software arranger that hosts Yamaha styles, but OMB works fine for me in real time. Live styler seems to work fine for Frank Rosenthal, so I would guess it's also a very good program.

OMB does not open as a Vst, but you could sync it to Cubase using the freeware Midi Yoke drivers, which act as virtual midi cables inside of your computer and allow you to link two or more programs together.

Regards,
AJ