I tried to figure out something like to float my MLT wort-in line in my HERMS. Nothing worked for me (no float) -- and I, too, worried about the food grade issue. I went with loc line (and the frigging loc line pliers). This allows me to reposition the return in any kind of configuration anywhere in my 15 gallon MLT. If I direct it just so along the side of my MLT, I get a nice whirlpool in the mash. I can bend it so it's a half inch above the mash, etc. etc.
Loc line turned out to be (for me) the perfect solution. The special pliers were annoying because I thought I could put together the 1/2" loc line without them -- but it was a lot more difficult than I thought. Bought the pliers for 11$ at mcmaster and the line snapped to in a split second.
I'm planning to figure out a way to swap out the spout tip (used for recirculation) with a sparge head.