I just installed my Drake II yesterday. I've read this concern a bunch of times on this website, and of course I had it on my first Toto toilet. There are quite a few posts here where people claim the tank doesn't need to touch the bowl, but the manual is very clear that the tank does need to touch the bowl on the three contact points.
I was in the same boat as you. I ended up using a small plastic shim on the back to fill the space, so it's now rock solid. I may try to re-set the tank, but at the moment I didn't have enough time to keep messing with it.
EDIT - I had a little time today and took another crack at it. It took a couple tries, but I was able to get the tank to touch on all three points without really cranking down on the bolts. Repositioning the tank did it.