Advice for 2004 Jetta fixing of AC/Heat vent position leakage

Hi, I had the classic old foam chunks blowing out the vents about a year ago. I did the "shortcut" of removing the foam I could reach, and resealing the flaps with AC aluminum tape through behind the radio. You have a very tiny space to work from doing it that way, and I think can only get it 80-90% done if you have "man hands".

Problem:
I noticed in even though my manual A/C-Heat vent position is selected to the normal cabin setting, that I am getting A/C-Heat coming through the defrost AND floor setting. Causing fogging on the windshield on cooler wet morning.

Since it could be some old foam got loose and is blocking one of the flap doors, OR the cable/mount for a flap has failed, I'm wanting to take on the crazy task of removing everything to get full access to the climate box to fix it once and for all.

Question: What should I have on hand to do that repair, other than more aluminum tape, goo-gone, MEK, etc.? JB Weld in case a tab has broken off? I want to be prepared since the car dash will be apart and not drivable. Is there any other seal or foam material you think I need? I've LOVE to hear from someone who did this "from what I hear" pretty involved task.

Thanks!

Haven't done it yet (though it's on my to-do list too), but maybe one of those blend door bushings that CoolAirVW is selling?

I'll make my own if it needs it. Thanks for the tip though.