A little tank wobble is normal with most two bolt tanks. Some of them will tighten down until the tank and bowls touch but many do not. Do not over tighten or you will crack the tank or bowl even if they are not touching yet. Tighten them until they are good and snug and you can usually see the gaskets on the bolts have compressed some. test it for leaks, if no leaks it is good enough.
That is one reason I like the mansfiled toilets is because of the 3 bolts and also the flush valve gaskets seem to last forever around here. Although they don't rate so well on the terry's toilet review I haven't had any complaints about them in the last couple years.
congrats on your new drake install,