I used the one that Agrazela and I had ventured into. The one other time I used this type of material was on a TB and it's still working well to this day. IIRC the issue you and I had with your gaskets wasn't a leak, but that they got dirty when they came out of the first build and were seemingly a pain to clean for the second build. I didn't believe that they caused you a leak, or I would have never used that.
On the maf and distance from the filter. That could very well be. It should be able to move closer to the TB easily. I did extend the maf wiring with solder and heat shrink. That shouldn't be effecting performance though.
There are really two things as I see it. One is the lean code. Which is possibly the maf location, leak in that vac line under snout, and very likely a tuning issue as well. The other item is the stalling, which experience says is a crank sensor or ICM. I'd aim to the crank sensor first.
