Hi Rotornut1,
I bought a set of those block adapters and an AN elbow to try the exact same thing. The problem I ran into was that by the time you put a AN12 elbow on them, you didn't gain any room over the RH solution. Plus, the inner diameter was much smaller than the RH elbows, so you would introduce a restriction in the water flow
If you could find a tight 90 pipe elbow (maybe 1 or 1.25 diameter) and weld it to the Meziere blocks, you may be able to buy some clearance and keep the flow. I never understood why the RH block exist out the side for one port and the back for the other. If they exited out the side for both ports, that would eliminate over 1 inch from the current setup.
Keep us posted with what you come up with and good luck.
Mike