Head gasket LEAK , I Fd up

I Fd up.:banghead: Did not check my block for being flat, and install a set of Mr gasket thin head gaskets. I got water leaking between the block and head. REALLY leaking, not just a seeping . The heads were surfaced and flat. Every thing was clean and dry. I did not use any head gasket sealer (copper coat)... I really don't want to pull the block down. So what do you think my chances are to fix the leak, buy installing a set of Thicker felpro FEL521SD head gaskets with the printOseal......or wait for it so snake oil , head gasket/ block sealer.
What type of block sealer WORKS ??? I Fd up.:banghead:
I had the thicker felpro 8553PT on before , I put on the thin MrGasket head gaskets .