I have a banjo counter with 32.5 inches clearance below the front edge. I am looking for a Toto ADA height toilet that will fit under here and have room to do potential repairs within the tank without removing either tank or the whole toilet. The Toto Ultramax is appealing, but at 29.25 inches to the top of the tank I'm not sure that there will be enough room. One would gain maybe 1.5 inches when the tank lid is off, for a total of 4.75 inches between counter bottom front and open tank top. My question is - just how many inches of clearance space is advisable? (I have replaced a flapper by feel with only about 3" clearance - also involved a mirror, flashlight and some arm contortions!).

I see that the Toto Supreme ADA is a similar style to the Ultramax and has a much lower profile (only 25.5 inches high), but the flushing system is one step below the Ultramax and that has me somewhat concerned.

Any thoughts would be welcome.