pike it an inch, or heat treat the belly , or reflexing the tips will all add the bit that you need. i wouldnt add a backing- i would be doing a belly lam before a backing, but you wont need either just to pick up a few pounds.
how long is it right now?
if its already short, reflexing the tips and inducing a bit of back set with a nice belly toasting will give you more than you need!
got any pics.