On a standard Holley I leave them in. Don't see any reason for removing them since that would require cutting them out and replacing. I get the odd carb holley that has one or two slightly loose boosters ( usually down leg boosters ). I have found that when I am glass beading them the booster will tighten up. ( kind of like shot peening I guess ) So I can even straighten the booster first if needed. One time I had to slightly peen the booster where they are swaged in and after media blasting was virtually undetectable.
Have not restored any Demon carbs yet. Some of those have removable boosters ( correct? ) Does yours?