Yes Alex that drawing is what I was suggesting, and not explain too well. I was looking for a photo of that sort of setup to link here, but your drawing gets it.
One thing to think about is the addition of a guidescope, which has to go on the top of the scope (otherwise it would be blocked), and just can't be mounted underneath. However, OAG setups will maintain that geometric architecture. A top mounted guidescope will move your geometric line upward above the dovetail if it weighs enough. Simple light guidescopes (like the ZWO 60mm) don't seem to offset too much, and centering it over the DEC rotation point helps.
https://goo.gl/images/BNVQ2Z