My home made remedy for the raised upper receiver rail with a standard AR height optic:
I used a Dremel to thin down the leading edge where the charging handle's stud (on the inside of the charging handle) would normally not have clearance, then cut a groove for the stud on the left side of the stock. The cheek weld is perfect for the ACOG now, but will be too tall for iron sights, unless I use standard AR height BUIS, I just don't like the extra hold over I'd have to remember. Shrike specific BUIS are being shipped.
While I was at it, I dug out a STG58 FAL carry handle I had sitting around for the last 10 years, and reduced the outside diameter of the loop, then used a Colt AR15 pivot pin (the old one that needed a slotted screw on the other side), then a screw I happened to have that fits the pivot pin perfectly. Barrel removal handle! This was done by a member (amphibian I think), it's nothing to look at because the FAL handle is beat up, but it works