it doesnt effect significant areas unless you do a iron sight to the rear configuration.
with the irons left in their slot and the RDS to the front, the mill slot comes VERY close to the extractor pin channel. this can be solved by shoving the RDS all the way back and milling a new more shallow slot for the iron.
AS a matter of personal preference I feel that the primary sight system should be the one up in your face when shooting thus I feel that the BUIS should fall in front of the RDS just behind the chamber.
AS far a deltapoint, I would stay away from OST and go with Bowie Tactical. they are the experts on the deltapoint and have installed many thousands more than OST.