Opinions please.

If I were to build a .40 size model of this fuselage out of blue foam (not a profile but turned on a lathe) and add a conventional built wing (edge 540 about 47") and tail surfaces, whats the chance of bringing it in at under 5 lbs.
I know some of you builders have a lot of experience with different types of foam and are experienced with the weights.
Appreciate some input.