You are very welcome.
I don't know how handy you are, but be careful when you drill the topcover for the mount. The steel was a harder grade than I was expecting
I used a prick punch and very small bit to drill a pilot hole.
If you don't have a bench-top drill press, this is a good excuse to get one.
Heh, you just gave me flashbacks of when I was trying this. I was attempting to mount a rail on a semi-cover on the cheap and went through several drill bits barely making a dent in that thing. I finally had to purchase a drill press and cobalt bit and that finally did the trick, though the end result was kind of ugly. It all kind of defeated the "on the cheap" purpose but by that point I was committed. I don't know what kind of steel they use on that topcover but I'm sure the army would appreciate having some. My rail extended a bit too far forward so I ended up relieving some material from the bottom to clear the charging knob slide so it would go all the way back.
Back on topic, I did mount a cheap small red-dot on it for a while, though it wasn't low enough to co-witness. I never really got used to it and just went back to iron sights. I have considered mounting a better optic now that I can afford it and may do just that if I manage to find it (recently moved and everything is still not organized).
I only recently learned of Richard's (BWE) passing so I'm glad to see at least Amphibian is still at it. I remember when Amphibian first invented this topcover configuration. I think he was the first person to ever even try such a thing. Back then he was making them for the Doctor Optics as I recall. I got a chance to try out one of his guns once and it was a sweet setup.