Gecko 204V is a great stepper drive. I just sold the last of mine and they did a great job for me while I had them.
You are handing them a tall order with those big steppers. The Geckos top out at 7A
Why have you decided on steppers over servos?
Quite frankly, cost and inexperience are the 2 major factors. If I screw up, it won't cost too much to fix my mistake, and maybe I won't get fired. (j/k)
The steppers I've spec'd are rated @ 4.0 A/phase. I'm hoping that they will do the trick. The parts I'll be making (right now) are all fairly small and speed isn't as much of a factor as accuracy is. If everything works out this time, I might be able to convince the powers that be to cough up the funds to go all the way. We have 6 Bridgeport type knee mills, and this is the 1st I'll be refitting, but ti probably won't be the last.
I appreciate your input. I've relied a great deal on info that I've gleaned from the posts on here. You (Simpson) and Hood seem to have the best handle on some of the idiosyncrasies of a project like this.
Thanks for your input
Keith