Danger, Will Robinson!!

How old (and good) is this bag? I'd go slow before irrevocably destroying a near-new WM lite-series bag; I might be a lot more willing to take a chance on a Campmor house-brand bag that was 6 or 8 years old.

Before you grab those scissors, you might want to post in the D-I-Y section of the forums for tips, or maybe even for supply sources or kits and plans to make a half-bag.

But, overall, your idea to modify something you already have makes sense.