Thanks for the replies so far. The Diamondheads do look nice, a buddy has one and really likes it.
I am not above milling off the rail on my gas block, have the tools for that and so much more.
Ive been looking them up, and its not easy to find FF tubes that are not cluttered up with rails. At the most, short rails on top and bottom, is all I would ever use. And most likely never use the top tail.
I may just go with a knurled aluminum tube and put a 3 or 4" rail under it.