mmmmm, i'd say not very precise. But can be reasonably accurate if you do everything correctly.
I think the biggest problem is the placing of points is very subjective, it is difficult to be on the same pixel everytime.
So if you dont mind being a centimeter out then give it ago, if not then i feel it wouldnt be the best option, or you will have to create a process that keeps the accuracy.
Plus you are from a fixed position imagemodeller needs at least 2 positions.
fazziebear