Not a problem. Get it skimmed only enough and get a thicker than standard Payen head gasket that will bring it back to stock. My one mechanic friend here in Bloem said he did it a number of times with BMW's that had heads skimmed to the max. Upon request to Payen they make a custom thickness head gasket for him. He said he had one made 3mm thicker than standard and the car is still running fine without blowing head gasket or anything.
I think 77mm is the stock thickness as I have a spare GX head sitting at 76.9mm.