It may or may not be too late in the season to try it, but I think this would be a good application for the
Nothing But Dewalts FP transmission. You get a 47:1 reduction in the tranny, which gives you a peak power RPM of around 255. Plus you should get a lot of torque out of it. Most importantly of all, you can leave in the anti-backdrive pins, so your motor doesn't have to melt trying to hold your arm in place.
Team 57 is going with this setup for a telescoping tower for all these reasons, though we're having troubles getting the parts. The clamshells are on backorder, so we've ended up buying a drill to cannabalize the shell from. then when our backordered shell comes in, we'll have a shiny new drill for regionals.