Taping correctly means not just getting the correct 'tightness' but making the diaper take up the correct shape for your body. So the correct tightness for one diaper or one person might not be for another, depending on their shape and size.
Getting a good leakproof seal around the legs depends on having the bottom tapes right. I find they need to be tighter on Betterdry than on Tena Slip Active Fit, my two most common daily wear choices. Then, getting a comfortable fit, that stays snug and supports itself as much as possible, depends more on the top tapes. Again, for me the Betterdry needs to be a little tighter to fit well. Of all the diapers that I wear regularly, the Tena can be left the loosest without compromising the fit.
For continuous wear, having things too tight can lead to skin damage, so I prefer diapers that don't have to be excessively tight around the legs especially, to get a good fit. I do like the diaper to be snug against me all over and not flop around, but the support pants are in control of that as much as the tapes.