Ok, could be improved
The scale length adjustment only allows for going up/down by 0.1 of an inch. This means that the Gibson scale length of 24.75” cannot be selected, only either 24.7 or 24.8.
Also, the gauge selections jump between values, e.g. I can select 0.045” or 0.047”, but not 0.046”. The difference in tension between 45 and 47 thou’ is large - 45 thou’ at standard pitch E is 17.5lbs, 47 thou’ at the same pitch is 19.3lbs. 46’ thou would be somewhere between, but it isn’t shown.
For the above reasons the app is not accurate enough. I don’t understand why it has these oversights - a huge number of guitarists play Gibsons, and 46 thou’ is a very common gauge, included as standard in e.g. string sets by Ernie Ball, D’Addario and others.