Losmandy dual scope platform for GM-8 (not G-11) and a set of 90 mm ID rings. Barely used, almost LN.
Those are sell respectively 115$ and 82$ by Losmandy. The lowest prices I had seen on internet ate 100$ and 74$ + shipping. You can have both of mine for a total of 125$, shipping incuded in continental US and Canada.
The dual scope platform has a GM-8 saddle on one side and 1/4 bolt and 2 aligning holes on other side where the rings are mounted. Rings are fix to a plate and have 5 in. of separation. You can use the platform for a camera.