Valve recess, what will I get away with?

Just had my 300tdi head skimmed, 6thou off (gulp). Valve recess should be 0.81-1.09mm for inlet and 0.86 to 1.14mm for exhaust, mine are 0.3 number 1 exhaust, 0.4 number 4 exhaust and the rest are 0.5. Had a 3 hole 1.5 gasket originaly. Machine shop don't want to cut the seats, say they would end up to thin and could drop out, my only other option is a 1.6mm no hole gasket. What do you all think, will I get away with this, the machine shop think I will.

Anyone got any idea about this?

You've already trusted the machine shop to do the work, I'd trust them to know what they're doing.

You'll be lucky if anyone's had exactly the same situation as you, so really you won't have much to go on other than engineering principles and empirical measurement. I say just do it ..