The doubling of the gasket is probably more a contributor to the seat-of-the-pants improvement than any restriction you've added.
You've begun on your way to creating a 'high-rise' manifold, a long known performance enhancer.
The screen obviously reduces the area of the intake. Might just help increase the intake velocity. I've seen that done with epoxy on some racing motorcycle intakes.
Looking forward to your follow up.
That's a completely different thing. the screen will increase velocity for the franction of an inch of it's thickness but the air will slow down again as soon as it's past it. using epoxy in the manifold/runners is to eliminate dead space and therefore eddies in the air as it flows through. it keeps the velocity constant and reduces destructive turbulence
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
Interestingly enough, a college used this trick to convert a car to run on Ethanol, this, as well as a bit of heat made the ethanol atomize to combust even on the coldest of days. The only problem i see with this ( as well as on mechanical injection systems" is that an intake block, will make you have to open the throttle more to get the same power, but with out an o2 sensor (i have one hehe) it will not know that it is getting less air than it usually does at this throttle opening.... Rich booo.