Head machining

7M-GE As these engines have trouble with head gaskets is .011 too much to remove from head? this one has been machined twice since I owned it. I took the head off my second cressida (blown gasket)and took it plus a head that had been machined already to get the best one surfaced and pressure tested and he did the one that had been machined before. I measured the difference as best I could and it looks like .011 has been removed from the tested one. the block on the good cressida looks to be a lot better than the one I had most trouble with but not perfect but I can not machine it. This cressida ran perfectly up until it suddenly spluttered and stopped and as I removed head I discovered the heater tap had broken which I assume meant almost instant draining. I am going to take a chance on the block surface but am worried about the extra compression from machining. Also, how much more can I tension the head bolts over recommended before breaking something? Plus any other hints on replacing head