Actually we're using a "smooth hud" style for this new campaign, so i'm not really sure we'll need a custom ammo meter. They all pretty much match. For the reticle I'm not really sure yet.
I think you're on to something with the cmt reticle, but smaller, rotated 45 degrees, and with the four large triangles longer and bisected by the circle, like a plasma rifle reticle with a cool circle through it.