Hi Greg
That's a nice looking platform! Personally I think it would be a shame to abandon all that work when perhaps a more accurate motor might help you. You'll probably go for a stepper drive anyway if you build another platform. So why not try the stepper system on your existing platform and even if it doesn't work you can use the motor on the new platform.
We use this stepper on our club platforms:
https://www.omc-stepperonline.com/cl...S19-1684S-PG27
I have one here I'd be happy to post you to try out. I fit works on your platform, keep it. Bojan might advise you on what he thinks of it for your purpose.
Rod