Over the past few days I have mostly been working on improving the functionality of the model, as well as checking the peculiarity described in the last post. From what it looks like, the fact that the inner boundary is halfway between the star and the outer boundary appears to be an intended part of the equations and is not some mistake made during the creation of the model. Other than coming to this conclusion, I have successfully implemented a button that will overlay the orbit of the earth on top of the habitable zone for comparison (shown below). I also added labels to the star menu so that it is possible to know which row of numbers corresponds to which property of the star. I also made it so that clicking these labels will sort the corresponding category (clicking the name header will sort stars alphabetically, clicking the spectral type header will sort by spectral type,etc).
I think that there are one or two more functionality things that I would still like to add, but other than those, I am getting pretty close to finishing the model. Hopefully sometime next week I will be able to finish it and release it for download so that people can mess around with it as much as they want.