Imelda, the bacon weave is easy to do. Just weave it on a piece of plastic wrap on a sheet pan and then you can put it into the refrigerator to firm up. After you season your pork loin then you can flip the bacon weave on the meat and tuck it or roll it on. I don't think I would use foil unless the pork wasn't done and the bacon was getting brown....kind of a guessing game, depending on how large the pork is, etc.
Norm usually does a nice glaze of BBQ sauce on his, on his meatloaf. I usually just do the bacon without a glaze.
Oh, and I find the thin bacon cooks up nicer than thick when weaving....JMO
I usually look in the housewares aisle of my larger grocery store for cotton string. Cotton is the main thing and not a synthetic or plastic coated string that would melt in high heat.