Based on an inaccurate scale and a guess, I think I put "somewhere" around 25 to 30 lbs linear force on my extended, 10" crank handle. Using simplified but 'super fancy' physics to analyze my Heco geared lift mechanism, the roof weight comes out to be 5.33 * crank force, or 130 to 160 lbs. That seem too light to me for my roof -- ~7' x 14' aluminum framed. Only 1 110w solar panel up there, plus 3 vents.
I did ask Bob Ward, and surprisingly, he said they never weighed either the aluminum frame or the newer all composite roof.