Hi Bob
Now that is a very well written motor document ,lots of info , i can see it coming in hand on phase two of the CNC conversion , when i change /mod the head of the machine . Thanks for sharing .

no problem about the questions , fire away i will try my best to answer them .
Being lazy i did do a one stop shop at Zapp ,, bought the motors,drivers ,PSU,BOB, pendant,screws, and nuts from them , at the time they were the cheapest for most of the kit , I found there service to be spot on , everything was VERY well packed and they were very willing to help with any queries i had over the phone .Looks like there not too far away from you .
As to the documentation i cant really fault it , Driver manual and BOB manuals are great , yes the pendant info is a tad iffy, but not hard to work out .
The belts ,pulleys,bearings i am just getting local .
20mm screws will be fine for the XY , but things will still be tight ,there is not allot of difference in the nut size , thats why i went for the largest i could get in , also there is less force required to move a 25x5 screw than a 20x5 screw , there is loads of room for 25mm or larger on the Z .
I hope take the time to share your CNC conversion with us here

Rob