As far as I can tell, having just built the same plane from scratch, it wouldn't be necessary to put the formers back in. The strength of the fuselage is the sheeting, which is 3/16th to 1/4 inch balsa. If I were you, I'd check for thin spots (over-sanding) and maybe reinforce them with thin sheet balsa on the inside. If the plane was built from the kit, according to the instructions, the only formers I would be concerned about are F5 forward. It seems to me that the majority of the weight problem comes from the engines. The original plane was designed to fly on Supertigre 60's. In my opinion, that's not enough power. OS 91fx or OS 120fs or similar would be good. I'm using Saito 100's and expect to have more than sufficient power. Who knows, maybe at 40 pounds you need the Quadras!! I have templates for the formers if you insist, but getting them in around the stringers may prove to be more difficult than than building a new fuselage. Plus, there's no guarantee that the formers from my plans will accurately fit your fuselage. An easy solution would be to order a fiberglass replacement from G&L. That's where I got my cowls. They're relatively inexpensive and probably save a ton. Well, a few pounds anyway
Don't know if I helped or just confused the issue. Make a decision you can live with, and "git er dun". Good luck!!
Steve