I have an HHA OL-5000 and like it a lot. However, I'm not quite sure just how your sight adjusts, but what would be stopping you from getting a piece of white paper with a sticky back and put it on the sight. Then just cut it to fit and put your own sight marks on it. Would this work? Are your marks on the back where you can see them?

And FYI, I don't adjust my sight for hunting. From a tree stand I set the thing for 25 yards and leave it alone. Hold a tad low for anything 20 yards or less and a hair high at 30 yards. Too many things going on in my pea brain to be messing with a sight when a deer is approaching shooting range.