I just changed out my gaskets and found the new run of the heat spacers are slightly thicker, and better quality then the old mid 2000's style. After a few tests I found a sandwich of fiber, tin heat and fiber sealed well and prevented higher alcohol based fuel mixtures from boiling off.
I used to run the factory setup - fiber, then tin then carb base, but then a few years back the design changed and the fiber gaskets of many manufacturers were roasting out in a season or less and leaking badly. So I swapped positions putting the tin on first on the hot-slot, then fiber on top.
The divorced choke location can be protected by using a higher temp protection paint first then Chevrolet Orange on top of that.