I'm not taking the time to research your gliders but a non powered, true glider, should be in the 5-8oz/sqft. The arf bird of time is a heavy glider and it has 8.2 loading. Cheap 2M gliders run under 8. Motorized and if you still want thermaling you still want the loading to be as light as possible, I would want no more than 9-10oz/sqft. 12 seems heavy to me, 21 I wouldn't even consider to be a glider. As an example my Giant Aeromaster biplane has better loading and it's one of the highest loaded airplanes I have out of a dozen gliders (some powered), 3D(like my U-Can-Do @17oz/sqft), gassers(the Aeromaster and my big Quaker, my avitar, that has 5.4oz/sqft), competition fun flys (real good loading) and a few scale jobs.