Actually - things like the Drum Dial measure drum head tension, they are designed to get even tension at all tuning logs (this is referred to as having the drum in tune with itself).
However, if all the lugs have even tension, but the actual tone of the drum is not within it's ideal tuning tonal range, then even tension has little value.
The point of the dial is to get the drum in a tone area that "sounds right" (like anthing musical - trust your ears) and then fine tune the tension.
There have been numerous thread in the drum "chat room" - a search could provide plenty of info.