A day and half after installing my AS Cadet 3 I discovered a small leak from the tank. The small portion that I can see with a inspection mirror and flashlight shows a small bead of water at the top of the rubber seal where it meets the tank around the flush valve. It then drips off the mounting bolt on that side. After breaking the cast iron closet flange during this lenghty install, I must admit to being paranoid about overtightening "any" toilet bolts! I did tighten a bit though but the shorter back and longer front points are making contact, so the rubber seal is compressed as far as it can go, I think.

I wonder if the plastic nut holding the flush valve could be loose? Does one use plumber's putty, Teflon pipe dope, etc. in these areas that aren't usually suggested?

I installed a Kohler sink earlier this year and ran into leaks galore! Leaks at the MAC washer, water wicking down the threads and one at the popup lever. It took plumber's putty and Teflon pipe dope to stop them.