The concept is cool, but
1) Anyone who has ever used a drum dial knows a common problem is just because the tension is even, it doesn't mean the head is perectly even and in tune, and usually a drum still takes some tweaking. This does not eliminate this step.
2) Anyone who has ever used a drum dial knows there can often be that on lug that sits at a much higher/lower tension than all others because of inconsistentcies in the heads.
3) Lugs can be inconsistent due to dirt, rust, lube, or whatever, so having the same # of turns of a key doesn't always mean each lug is even with the rest; i.e. the same reason torque wretches have never been popular sellers.
4) And so like the drum dial, torque wrentches, and other "tunning" devices, this only gets a drum in where it sould be in tune in theory, but theoritically in tune and actually in tune are not always the same thing.
However, the biggest hurdle that kills this is $75.
A drum dial is $59 and effectively does the same thing, in letting you get an even tension around the drum. Granted, your device sameves some time, but it's not a competitive price point compared to a drum dial.
A torque wretch, while not popular, sell for $15-$29.
The Tune-bot debuted at NAMM, and measures actually tuning, and not theorical tunning, for only $14 more dollars at a $99 street price. Granted, not everyone buys into the Tune-bot being a viable item, still, it's a competitor in the market place claiming to do more than your product for not a whole heck of a lot more $.
You product won't work on Sonor drums, may not work on Gretch, which granted only elimantes a small part of the market, but that is not a problem other devices have.
If this could sell for around $20-$25 street price in a retail store, I think you could sell a decent amount of units. But at $75, it is not price competitive with other products that acomplish similar results.