Sound deadening for back wall of cab recommendations?

In my 08 AC, when I removed the back wall to install a rear-wall molle panel, the tacoma's tin-can effect had increased to an annoying level, so sound deadening was a priority.

I wanted to maintain the ability for air to pass by but, in my opinion, the cab didn't need a breather that large, especially since my rear wall panel would not be reinstalled.

I had read one thread here on TW that mentioned the noodle, but was unclear in depicting how it was used. I took my time to create a soloution, as i knew, like most other things, it would just suddenly occur to me.

In my mind's eye, I kept picturing rubber flappers in each channel of the vents, similar to exhaust ports on the transom of a boat with an inboard motor. I found some 1/8" gasket material in my tool box that was purchased from lowes, rough cut it to fit between the wall and the front of the vent, traced the outside, then pushed down so the walls that divided the channels left an impression.

At first, I thought the 1/8 would flex enough to achieve my goal and I had cut the material to fit almost exactly into the channels, but after placing it there for a test-run, there was too much resistance for me. I also didn't know how it was going to paint it black, so I brainstormed some more.

I decided I would go ahead and cut/prep the flex tape i would be using to attach it to the wall and that's when it hit me. I trimmed about 1/8" off of each flapper, and cut flex-tape big enough for 1/2" extra on 3 sides, taped it on, cut pie wedges to wrap the corners so the edges terminated on the back side. It's still not flexible enough for perfection, but it blocks the road noise and seems to allow enough air to flow to serve is intended purpose.

If I had to do it over again, I'd use 1/16" gasket material and cut each flap into 3 separate pieces that the tape holds together so it bends more eadily