My neighbor and fellow quilter comes from a family who owns a dry cleaning company. She uses Magic Sizing only, and says that is what the company uses for any fabric pressing.
Last weekend my DD1 was making a wedding dress for a friend and she used Mary Ellen's on all the layers of sheer and others --it came out spectacularly with just the right coverage. Of course she used my whole 16 oz. bottle.! I went online and found a gallon from the company that makes it cheaper than any other,even on sale.