deck finish difference for MLS head gaskets

What's the difference in deck finishes between regular head gaskets and MLS head gaskets? And why?

In the old days the cutters left little grooves and everyboy said that's fine it helps it grip. Today everybody wants MLS gaskets and Cometic says they want a finish of 50RA or smoother.

So 50ra is like a "ground" finish versus a "cut" finish ??

So using MLS gaskets definitely can't be used on a cut deck?

Here's a bit of a dilemma ... what would you do with a cut deck but out-of-the-box aftermarket aluminum heads that have the smooth surface ??

Use a Fel Pro permatorque composition head gasket
Or have the block resurfaced,refinished, for the 50RA finish
Copper head gaskets need a fine finish like the MLS head gaskets do

I used MLS gaskets on my 416 stroker engine in my drag car, couldn't get them to seal, leaked antifreeze on both sides. Called the manufacturer, was told to re-torque them, which I did, no change. Talked to my engine machinist, he said he had many customers using them and had never had any problems. He also said that different alloys will cut differently, even using the same cutters. You could see the ridge marks on the gaskets when I pulled the heads. Went to Fel-Pro severe duty gaskets, have had no problems whatsoever.