Leslie motors were indeed intended to drive the vibrato scanners leaving the original X66 motor (running too slow) for the slow scan celeste. The X666 now also has a Leslie sim built in. I'll be playing it on August 13th at the Wight Hotel, Sandown, Isle of Wight, around 7.30. I'm sure all will be welcome!
I hope to record this direct to digital recorder or laptop, and capture the video in full HD. Marrying the two things up later will no doubt take rather longer than the concert will last!
So that 99p bargain E550 will be serving me well, as the E550 did back in the late 1970s!