Adding rotary Axis

[Demusman]

Thinking of adding a rotary axis to my machine and looking for some suggestions.
Right now I use the ETH400 with port 1 going to a Gecko G540. All 4 ports are used.
I would like to add the 5th drive to eth400port 2.
My initial thought was to add a gecko G250x since that's what the G540 uses, but then I thought maybe I'll try for some ideas from people with a similar setup.
Anyone have thoughts on this?