Trying to decide which gas block for a 18" SPR barrel from WOA. This is a build that I am helping a friend out with. He plans on giving it a rough / beat up paint job, most likely using Krylon or Duracoat

I figure that after it's coated, it won't be any easier to slide the gas block on, since I've heard that SPR match barrels from WOA are tough to get set-screw gas blocks on. Should we just get a Rainier low-profile match gas block that is .755 to accommodate....or just man up and work a regular .750 block on...or try a clamp on gas block, like from DD or YHM?

I'd go with the YHM clamp on...

Not sure what rail we are going to use yet, but I am reading that the YHM clamp-on is not as low-profile as most. Wondering if this will limit the number of rails we can use?

I'v got one under a SLR Lite rail.  Vltor would be another good option.  It's a tad smaller than the YHM...