I also switch up...not arrangers but a 2nd or third keyboard. Sometimes, it's the kind of music that makes me modify the equipment.
Generally, I use an SK-1 on the bottom and either an old MS-60 or SD-5 on the top.
More conventional jobs get a nice electric piano on the right hand. On others, I use a synth. For bigger jobs, I sometimes stack the synth and the piano.
Ya just gotta remember where you are wen it's time to make a quick tone change.
FUN FUN FUN!