Made plenty of tape loops myself over the years, including replacing the tape loops inside of those damn 8-track cartridges for my reverb unit. What I generally realised is that for best playback there should be no tension (or only minimal tension if it needs be) whatsoever on the loop. Basically, it should be running freely…….
I had some faulty tape players which moved the tape quite fast and liked to chew it up, so that didn’t allow for super loose tension but, nevertheless, it always needed some play to work nicely.
As for the scotch tape: I used any kind of scotch so far. On one side, on both sides, back and front. Anything. Nowadays I usually use proper tape splicers and, when available, splicing tape as well which I apply only at the back. But if I don’t have splicing tape I’ll revert back to scotch and that works fine for me…….anyhow, I suppose it all depends what you want to achieve…….using coarse methods may lead to more gritty results, of course.
Perhaps a really good resource at the moment is: https://www.youtube.com/user/amuletsmusic/videos
This gentleman does a lot evolving around tape loops and I’m sure you will find some clues on his channel, if you don’t know about it yet………good luck with your tape endeavours.
