Obviously you're on the edge. I don't know if taking your motor to 11.0:1 and improving quench will solve your problem. Maybe. If you ran a 0.060" gasket in the past and it worked better for you, at least you know the results.
You could also consider moving the the intake closing point, possibly in combination with the .051" gasket. If you retard the cam 4 degrees that will make a difference. Enough, I don't know.
Do you know what your current cranking cylinder pressure is?
