If you notice the upper full keyboard has more FLUTE (TIBIA) tabs than the lower.
Which to play through the Leslie speaker the BLUE TABS on the left next to each keyboard must be depressed ( turned on).
So usually you don't want much FLUTE in the lower manual if you have FLUTE (TIBIA) if you are playing FLUTE in the upper manual. That is, mix the voices for the most convincing portrayal of a melody and it's accompaniment. The main thing about organ playing is learning how to properly ( for the most tasteful playing anyway) REGISTER the organ. Here is a blog I wrote about the 625/630 Wurlitzer organs, as I played mine a lot! The organ is pretty easy to learn the features intuitively really.
