There is a problem testing light weight construction vs heavier construction. While unloaded shape can be maintained very much consistently, loaded shape cannot.
If you have ever placed a piece of tape on your leading edge while the kite is inflated, then deflated it, you will get an example of how much even the heaviest kite material stretches. As the kite deflates, that tape will "wrinkle" showing how much the LE material was stretched under load.
Thus, when you change material, you also change material property. This is fundamentally unavoidable. Stretch under load (curve on a graph), stiffness, surface drag, and the proceeding in different directions (axis), all can vary significantly enough to give the same shape kite a completely different feel with different materials. Given the number of variables considered before you even get to weight, well.... you can see there is a problem in comparing them.
The best indication that these other variables are in play is if there is a lack of consistency in difference to the feel of multiple constructions. But short of a blind flight test (ever hear of something like that being done?) comparing the same color and design kite with multiple testers, we are kind of stuck speculating.