Thanks for the responses 🙂 . I picked up some pin striping for cars on amazon.ca for 2.99$$ and that works really well and doesn’t leave any sticky residue behind. I think it was 1/8″ width. My teacher used different tapes and since showing her that product she is now using it . I also picked up a fretless finger guide which is vinyl and not sticky at all. Seems to work really well :-). My teacher hasn’t had any studens use it before so I’m the test subject I guess.