Most of the canting rear sights that I have seen just allow the rearsight to rotate about the sight line, so that you do not worry about canting the front sight. Of course with both 10m Air and 50m Smallbore as you are only shooting at one distance so do not need to have the sight vertically above the bore line like you do with FT or Fullbore TR in order to make range changes without adding a horizontal correction. In fact many shooters cant the rifle, especially in the standing position, but do not bother with cantabile sights. you soon get used to what corrections you need to make.
The raiser blocks in the link will allow you to have the rear sight adjusted so that it is vertical, but it will not bring the sight line vertically above the bore. But then you do not need that in ISSF AR or Smallbore events. I don't think you would be able to set things up to allow the vertical alignment of the LoS and Bore Line within the rules, especially for AR.
