What size/power scope? About 3X and up you don't need to clear it and extreme high mounting presents it's own problems. Most opt to change the front sight/gas block or use a red dot optic instead. A bit taller mount for co-witnessing is about the limit you want to go. " Stacking" mounts with a riser device is not a good idea, IMHO.

Please don't think I am criticizing your efforts, just trying to help.