My trick to solve the cant problem, use a level when hanging targets. I have been known to snap a chalk line on the backer that is measured using a line level. That lets me lineup along the grid lines on a target. That has helped me at 100 and 200.
Wind is a factor that I can mitigate somewhat getting to the line at 8 on opening range time and usually calm until 10. On good days it might be ok until shortly after noon.
I never really knew about parallax until reading a short paragraph here years ago and bought a good AO scope, learned a lot from that exercise.
Just putting this out there, someone may learn something from it.
