I'm running a Saito 82 inverted in my Seagull Spacewalker II. Standard Tank installation and have not had any issues to date with cooling, Lubrication or Carburettor flooding. I have used a different exhaust outlet pipe between the Engine & the muffler though. (I got a longer 90 degree one from an earlier engine). The standard (45degree) pipe didn't allow the muffler to clear the cowl very well).

Irrelevant to the original post but I did change out the standard pushrods as it seemed quite easy for the airflow to overcome the control surfaces (especially when I had the 82 wound right up and on "high" rates)