I don't know too much about the technical aspects, but I do know that there are some Lowreys out there that have a good reputation. If I am not mistaken, Garth Hudson of the Band used one in lieu of a Hammond. He certainly got some great organ tones.
Try
Lowrey Organs Page *Keyboard Systems - Lowrey Manuals*
for starters. I just googled lowrey organ manual. Should be able to find something useful pretty quickly.
Edwin