Thanks for this info. I got more like 1/6 of pound per sq foot in other sources (about 800 grams per sq metre)After all that, lets remember that a really well done square foot of bond line made from slightly wet micro weighs about 1/8 pound.
Would you compare fullfoam wing to Cri-cri like wing ? 1/4" foam ribs with spacing of 1.8" at we first half of the winf, double that on other one. And with 100kg/m3 pvc foam, you have only 0.8/0.4pcf of average foam density per span.. And 1/8 of original skin to foam bond area..