Toto Drake tank leak

I just installed my 3rd Toto Drake in the 3rd bath. The 1st Toto the bowl leaked at the tank bolts. After tighting more several times the tank cracked. I followed the directions which had no plumbers putty added. The tank cracked at the screw. $100.+ for a new tank. I puttied the connections this time had no leak. When I installed the last toliet we had another leak at the screw. Drained and added the putty. Today it is still wet at the screw. I am a little scared to tighten too much.
Any help???

We always sand the inside with emory cloth.
No putty.
We install hundreds every year, but have never broken a tank.
Jamie also gives the flush valve nut on the bottom of the tank a bit of a turn with large pliers.

Instructions below.
https://terrylove.com/forums/showthread.php?t=743

Thank you. I will start over today and do it your way.