The Dawson rail is the one everybody I know that's mounted one has used...but that's only a couple of guys and to be honest I have not shot their guns, although I can't see why there would be an issue. They are both 1000+ rounds a month guys.
I am not saying any other rail is not up to snuff; I don't know. I would probably use a Dawson myself, just on the strength of the recommendation of the couple of guys I know. But others might be equally good.
What I can say for sure is that not all 1911s are created equal (as we all know) and this is manifested in at least some instances in the dust cover grind. Some 1911s have the dust cover ground out of spec, and the rails will mount, but not line up properly.
I don't know how common this is; I saw one case on the internet on M4C. It might be rare, I'm not sure. I can't visually identify a problem in either of mine, but it might be hard to tell without a rail there to compare it to.
I didn't see you mention the manufacturer of your 1911...although I guess I would have to admit that I wouldn't know which manufacturers would be prone to doing out-of-spec dust covers anyway - however I bet I could give some good guesses.
