Ian, aren't 147RV's GREAT? Not as powerful as 122's, but I still use a 145 and a 147RV with my B-3. And, I often use a pre-amp and a 335 Gibson on solos. With a heavy set of strings and a little practice, you can get a decent walking bass line and chords. Absolutely no controls on the Leslie or pre-amp, except the bar/slider for the reverb and limited volume control on my foot pedal/pre-amp, but the sound is always fabulous.
Looks like I went thru the same keyboards as you, including a little M-100 and a 145 (no reverb).
Russ