Hi Chris
Remember that you still have to get an F5 light cone through the focusser before the 1.25" star diagonal, so the back focus is quite long and a 1.25" draw tube won't cut it, a 2" focusser is mandatory .
The easiest lightest solution is the JMI 2" `reverse' Crayford with 1.25" adapter( as seen on the last 3 Ozzie/Kiwi binoscopes). A Chinese Crayford would also do, but there is a big weight penalty there
Mark