Front to Back Movement on Drake Toilet Tank

I recently installed a Toto Drake, and everything went pretty smoothly.

The only small issue we seem to be having is there is some movement on the tank when we flush. We took it off and reinstalled it, and still have the same issue (although a little less than the first install). It seems that the gasket although a necessary component to installation is causing the tank to sit too high and we cannot get good connection to the bowl. The instructions state the tank should touch three points in the back, but we are getting more contact with the front and not as much on the back.

We did have to shim the bowl to be level on our floor, but we did not think this would cause an issue with the tank sitting level on the bowl.

We are unsure of how to correct this problem. Has anyone else corrected this type of issue?

Thanks so much.
Meredith

If we shim a bowl, we pin the front of the bowl down to the floor.
I would rather the bowl touch in front, then be level.
Since the floor is not level, hopefully it's low in front, that puts more water in the bowl.

If you tighten the tank, it will touch the cradle. You may need to use the other arm to push the tank down.

If it's not centered, start over, placing the tank centered over the inlet on the bowl, and then start to tighten.
Once it has been placed on off off center, it wont pull itself back to center.