I havent read through the comments on here, but I have 2 suggestions for your calculator.
I had issues with importing images I took from my phone of the estimated shot I was trying to accomplish with my camera. When I import the image, the FOV of the camera distorts my image and makes it difficult. Perhaps an option to have the imported image be independent of the degrees of the camera?
Second, and an even better feature that should be fairly easy to work in would be a exportable or printable list of materials based off what is on the calculator screen.
15 cameras:
(10) Samsung XVI29 (random part number)
(5) Arecont 5185 (or whatever)
Some sort of bill of materials based off what is on the calculator would be pretty valuable.