A bit left of centre!
I've decided to mount the Borg scope to the side of the main scope. Using it as also a counter weight going from eyepiece heavy 31 nagler to eyepiece light 7.5 Le.
Needing 55mm of aft travel of the Borg scope to adjust weight to equalise balance. Have in the past adjusted the dew shield or tightened the mount to suit the eyepieces.
Used a 200mm macro photography rail which gives me 120mm of adjustment including micro 1 rotation = 1.06mm .
Includes push button for fast adjustment and lock down knob.
You could also use a dovetail with a small saddle clamp which would achieve the same outcome without the micro adjustment.
One multi-use telescope - visual/imaging/finder/and now counter weight
Cheers