Is that the only way? What about a single lens, ground with your cylindrical correction* attached to the rearsight? Plenty of pronecand position shooters do this. And the lens is squarer and better centred to the sightline.Same here. I have a moderate level of astigmatism which means that if I wanted to use irons I'd have to wear trifocals or progressives.
*and +.5 on the distance for a more comfortable focal length.