Immersion chiller materials question

hey everybody, a friend and I are about to make a couple of immersion chillers, and I had a couple of questions:

1, is there a different between utility grade copper tubing and type L, aside from type L being twice as expensive. the package on the utility grade stuff says it's good for water service so I'm thinking it must be food safe... but I was still wondering

2, is there a specific type of tubing that I need to use? I found plain old clear vinyl tubing at home depot, but I'm not sure if it's food safe (I'll have some tubing left over after I'm done with the IC so I was going to use it for racking, bottling etc) is there a specific type of tubing required for racking?

1. Not sure, but copper is one of the elements, i.e. it's a basic metal. As long as the tubing is solid copper it should work fine. Now if the more expensive one is twisted inside in such a fashion that it creates turbulence in water flowing through it, that would theoretically make it more efficient at cooling the wort. The idea there is that the entire cross-section of the stream of water is constantly getting brushed up against the side of the tubing where the heat transfer takes place. But somehow I doubt that's what "type L" means.

2. Nah, plain ol' vinyl tubing should be fine. It will get sanitized anyway.

Make sure your tubing won't wither under heat.

The walls of Type L are thicker than Type M/regular stuff... I would use M because you wont get any better efficiency using a thicker tube. In fact efficiency would probably suffer with L