If you look at the first picture Dave you will see that I have replaced the original GM-8 mount head with a G-11 (longer bearing plate which should help with flexure and offer more support for the Dovetail plate). The original head (its a round "C" series mount plate) is the mount head on the left side of the dovetail on top. I then used a GM-8 "D" series head on the right.
It is probably overkill, but this setup allows me complete control over positioning of the scopes fore and aft and side to side for good balance. I'm gradually marking mounting plates and dovetail plates with the points of balance for the different imaging equipment setups I may be using at any time. So swaping them over and re-balancing is relatively easy.
Using Losmandy gear it goes without saying that its nice and stable but also that its not cheap.
I managed to save a bit by getting the dovetail plates machined free through a friend and buying the additional plates from the US.
One disadvantage of doing it this way is its not light. This setup adds quite a few lbs to the system. If you were to buy the same system from Losmandy it would add an additional 7.25 lb to the mount. Then there is the weight of the additional dovetail plates, around 2 to 2.5 lb each. But boy is it solid
You could swing a C-11 of this baby with a 4" refractor for a quide scope np at all. Assuming your mount could take it of course