Clear packing tape is somewhat effective, but it seems to want to snag and start to peel up and peel right off overnight. I've had more problems with that stuff coming off than failing to stick.
OTOH, packing tape is pretty popular as a tape reinforcement. Tape quality varies quite a bit though, so you may have to try the grey tape from a few different local sources to get something that works well. Is sticky, is strong, tears evenly, is heavy/thick, favorable texture.
If you like the texture and performance of duct tape over packing tape, but don't like the "grey tape look" on your diapers, I'd suggest getting some white packing tape. It comes in all sorts of colors and even patterns nowadays, usually available at any big box general or hardware store.
Also on the line of being able to untape and retape often for potty use etc, I'd really suggest just perfecting the "diaper shimmy" to slip out of and back into your diapers. That's what I do, the only time I lift a tape is to snug a cloth-sided tena slip after a bit of wear.