IMO, send the open chamber heads back and get the 60779 closed chambered one. Use a .050-.070 head gasket to get your quench distance. You aren't going to get any quench with those open chambered heads and stock pistons.
It was my understanding the .060 ones are the same as the 60779, just clearanced for stock positive deck pistons? Wouldn't it be the same to deck the these down and get the same quench distance than it would be to add a thicker gasket? Unless their quench pad is different or angled like the stock open chambered heads.