I do not have that new system, but one thing I did to ours that did make a very strong difference was this. I went to each vent and removed the diverter. I should pop off fairly easily. I put small pieces of PVC pipe in the vent inside to prevent the racetrack duct from collapsing. Then I used silver HVAC tape around the plastic vent insert to seal it from allowing any air to escape into the attic. On a few, I found that the plastic insert was protruding up into the vent as much as an inch past the styrofoam insulation. In those cases, I cut the vent down with a razor knife to be flush with the duct work before taping it. Did the same to each return vent.
I found that the air flow increased dramatically on most of the vents, some more than others.
Got the idea from Gordon Hallof, a fellow Marine of course. He did a really detailed write up on his work on this. See his post here...
https://www.montanaowners.com/forums...highlight=duct