I stressing out over this next upper build.  I have a 14.5" Socom barrel with a Vortex FH thats not permanently attached yet.  I'm choosing between the KAC FF RAS and the RAS II.  

Now if I install the KAC FF RAS it will be on there for good after I permanently attach the FH.  If I opt for the RAS II I can take it off any time I want if need be (the FH does not need to be removed to take off the RAS II).

I'm more accustomed to using an Eotech, but am willing to give the Aimpoint a try I guess.  If I choose the RAS II it looks like I'm going to have to with its bump thats intended for the Aimpoint optics.  I would love the Acog but its too much $$$ right now.  

Basically, this will be my 'go to' and kick around gun.

So, which RAS should I choose???  FF RAS or RAS II ???