From how you play, I expect you have at least a few Reginald Dixon albums!

It might be worth listening to a few medleys and note how often he changes ranks and manuals. A theater organ on full swell can get pretty fatiguing after a section or so! They really were invented to replace a theater orchestra, so make full use of each section, play colors off each other...

That’s really the fun with the arranger. You really aren’t just a player any more. You are the maestro of your own orchestra! Give some of them a rest from time to time, feature some of the harder to hear instruments, mix and match different colors. It’s so much fun..!