To keep freeflowing air from going through the holes in my recessed lights, I have heard of a "tophat" to cover the recessed cans with. I cannot find them on the internet.If I fabricate them from sheetmetal it would be too heavy. Anyway,is this the best way to cover the cans? If I insulate up against them, they may overheat.Also I have heard of a ceramic spray similar to paint, that I could spray the bottom of the roof decking to insulate from the radiant heat on the roof,any input here? I am open to suggestions and advice!

Thanks in advance!

Rod