Very cool…so your calibrating the picture as canvas? I just did video on how to use picture and scale it to size. I normally just take end width and width near handle and connect them for my saw blades.
As far as cutting…
I remove 2 slots on my crossfire pro so the saw can lay flat since handle is thicker. Then mark 2 or 3 tiny spots on saw with marker and move firecontrol to each of them until i get the saw positioned to line up. I haven’t got that serious into cutting saws but do have a really cool one I planned on doing with guy holding chainsaw and big tree which I’ll post when i get around to it.