need some help confused

sorry but hgf related just removed head on my sons r25 due to oil in the expansion bottle, no coolant in the oil and no loss of coolant ,the car has covered 40,000 miles (had it since 19,000)has been well looked after and has never (afaik)been overheated, my confusion is which head gasket to fit as have read to fit a mls some say the liner heights have to be 4 thou and even, and level or uneven liners use elastomer, but mine are just 2 thou the price of the head gasket is not an issue but really only want to do this job once and he will be keeping the car, also what about skimming as if i take it to a machine shop and say only skim if needed they will just skim it anyway and say it was warped what do you think cheers ?

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