Option 1, cut down your fsb and make it a lo pro block. Then you can slide a longer rail on it.
I also think Daniel Defence makes nice 2 peice quad rail that will work with your curent config.
Assumption is the mother of all ****ups.
Know what you know, Know what you don't know. -Paul Pedzolt
"Jack of all trades, master of none, though oftentimes better than master of one" -Mynshul