You shouldn’t need to change the DIP switches and you don’t have to incorporate a dedicated driver for the rotary. If you want a dedicated rotary driver, Ruida has firmware released for the 6445 (not sure about 6442) that dedicates U for rotary operation allowing for laser fire commands while the U axis is moving.
Traditionally (before this firmware was being developed), machine builders installing 6442 and 6445 controllers would incorporate a common 3 phase stepper driver and switch it with a 3 position rotary cam switch to a 3 pin XLR / Aviation Plug Socket connector: