I finished assembling the Z carriage, I had to reduce the flange on the anti backlash nut for the Z axis to fit the space in the carriage. Mounted a temporary end stop for the Z axis, it limits the travel a little bit but it will work until I can mill smaller PCBs to make the proper end stops.
I got the wiring hooked up for all three axis to the temporary RAMPS board, currently all three axis are running in full step mode so they take 3600 steps to move the carriages an inch on the 5/16-18 threaded rod I'm using for lead screws. The highest speed I can currently run them at is about 125mm/min, I suspect with some lubricant and a bit more tuning I can get it a bit higher but in the end the best way to get higher speed if needed will be to switch to a higher pitch lead screw.
All three axis now work, I haven't yet done accuracy testing on the other two axis. I'm currently using Marlin firmware and Pronterface to do the movement testing. I'm hoping that I can get a couple good circuit boards out of this setup so I can mill the final PCB to run GRBL with this machine.
My next step is to design and build the Dremel mount and attach it to the Z carriage.