First, 1-9/16" from the tank to the wall is fine. No idea why someone would tell you otherwise. Second, sounds to me like the tank either wasnt tightened enough, the tank to bowl gasket was improperly installed, or there's some debris between the gasket and the bowl. I've installed numerous Drakes without incident so I'm inclined to think its improper installation. Some tank wobble can be expected, but not to the point of leaking. Third, check to be absolutely sure the toilet is leaking at the base. Sometimes water leaking from the tank will run down the back of the bowl and can appear to be a leak at the base. Also check the supply tube to be sure its not the culprit. If in fact the toilet actually is leaking at the base it will need to be pulled and reset.