I have the full Chevy liner setup and I generally like it with a couple drawbacks:
- In general, the Velcro they supply to hold everything up is lacking. It stays, but not great, on the seat back.
- if you do the rear seat floor liner, where they interlock together never stays and creates a lumpy look right in the middle of the liners.
- because the rear seats can move forward and backward, the others will leave a gap open as you said, so Chevy made theirs have a “flap” that would bridge the gap with the seats down. Because of that, the extra flap tucks under the cargo area liner and you can’t Velcro all of that down because it needs to move (the flap bottom, top or the floor liner for like half of its length). I found my rear liner moving all over the place when I drove which was extremely annoying.
My solution to all of the above was cheap and easy: more Velcro. I bought 2 packs of industrial Velcro from Home Depot, put some additional on the seat back and some additional under the rear liner to supplement what Chevy provided and a few pieces under the rear floor liner junction and it’s much, MUCH better for like $10.
I hear good things about Husky, have not used them though, but as much as I used to like Weathertech I feel like the last maybe 6-7 years their products have gone way downhill and I’ve gone to the Chevy product and have been happy.