I bought one of the Bushnell TRS-25 to try on my AR. The issue is, I need to raise it up some to co witness with the irons. I have a 1/2" riser that will work, but it could stand to be a 3/4" riser. I have found a couple 3/4" risers, but they are all like 5" long. I need one in the 1 1/2"-2" range preferably. Anybody know where I can find one like this?