I have adapters stacked on my car for months now. No issues. It's actully a very common pratice, especially with a FI setups. The Greddy plate I have actully uses a two gasket system for there universal. So when I was playing with it I actually saw I could use both gaskets (the smaller and larger one) and the would seat perfect up against the GTM sandwich plate.
But you could just buy the Greddy plate that's a all in one thermo plate with ports for your gauge sensors.
This is the part where it's universal where the gasket rings lay. I put both in. They seated in the above right picture on the solid part of the surface. They fit perfect without the inner gasket collapsing within the open portion of the thermo plate.
