I stopped by Autozone this evening and the closest thing I found to copper tubing was this kit by Sunpro (
CP7584). I went ahead and bought it in case this is what I need, in which case and have it on hand and ready to go.
It turns out there is a listing for more copper tubing on the website (
Gauge Line Tubing), but I didn't see any of it at the store I went to.
Hoping to do a check on the original tubing before heading to work tomorrow.