I decided to go with a Geoptik dual saddle that I had spare, instead of making a new rig. I slotted one end of one dovetail for lateral adjustments (ignore other hole as this was already present in the second hand dovetail), and for vertical adjustments I simply filed the base of one ring in several iterations until it was as close as possible. I’ll try it out and see if it’s ‘close’ enough. So its now all sitting balanced and ready to go. Next thing to sort out will be controlling two came