Two things.
1. I am pretty sure the AMT encoders will not fit the 1/2" backshaft on your servos. I used US Digital E6s, and another builder used US Digital E5s.
2. No need to buy a power supply. You have a big 230V/60V transformer in there. Unwrap a coouple turns and drop it down to about 57Volts output. Then wire it into a big bridge rectifier. I used a 100 amp one that came premounted on a heat sink. You will have right at 78VDC. Then slap a couple big ass Mallory capacitors on it to virtually elimiate voltage rippled and you will have a rock solid 78VDC power supply to push into your Gecko drives. The most expensive part is the capacitors. In my build thread I posted a link (a couple times) to a page that will do the math for you.
Bob La Londe
http://www.YumaBassMan.com