I've got a setup in this configuration. I use a Daniel Defense gasblock and it sticks out approximately a 1/4". I think it looks pretty good. The 10" rail is a nice balance between length and weight. The 14.5 middy is the softest shooting non compensated setup I've ever shot. I like the weight of the govt profile with this barrel. For me, the featherweights are too easy to overswing on targets. A lightweight rail with a standard barrel provides for a nicely balanced rifle when running and gunning.
As for rail length, I've really been digging the 10" setups. I've got the 10.0 lite rail on the 14.5 middy and a 9.5FSP on an SBR and find they're about the perfect all around length. I also have a 12.0 FSP on another 14.5 but with a carbine gas system. After using both I've found that functionally the 12" rails are nice for 16"+ barrels, bipods and 12 o'clock mounted lights. If you're not in that category I'd recommend trying the 10" rails.

