Block tubing, got some questions.

I gotta ask this again , are you guys using L , OR M , 1/2 plumbing copper ?
Have any of you investigated refrigeration copper ?


I did a little research on this when you suggested it before and very little info was to be found. I bought a 6 foot piece of soft 1/2 inch copper pipe (5/8 outside) and cut it up into 10 inch pieces but really didn’t want to risk drilling this block since it was already machined. Bad this have been know to happen.