Thanks mjolnir. The configuration is X head, Y table, Z head. Just like what you describe first. Thats how my firmware is set up currently.

I will probably go with a NEMA 17 first, and design the bracketry to accept a NEMA 23 just incase the 17 cant handle the weight. Although I suspect it all comes down to the DVR8825 drivers as you say, being the bottleneck. I am sure if I boost the current to the 17 it would be a torquey motor, are you saying that 2 amps in a 17 is the same or close to 2 amps in a 23? Which motor works more efficiently?