Hi conehead, I took a course several years ago from Sloan and the Sloan flushmate.
Believe me the last thing you want is a pressurized flushing tank with children around.
I am not too fond of Gerber plumbing products as I normally spec Crane toilets.
Gerber is a decent product and can be fiddled with to give more volume for a decient flow.
Try dumping in 5 gallon pail of water and see if these toilets take the volume?
Try to find out if your installing plumber installed a 3″ soil line or a 4″ and if he used crappy plastic or the longer radius cast Iron long sweeps for the toilet drainage.