Re:
If you are using tape then clean the rim.
The cheapest nail polish remover will soften the glue enough to let you scrape it off.
I have a knackered old screwdriver, flathead, with rounded off corners that does the trick.
Tufo tape is great, Jantex lets the tub slip, bending the valve and letting the tub balloon as it's stretched too far. I've had that happen a lot.
Richie