Air sealing around can lights. Ideas?

[beatr911]

Kinda new here, mostly lurking.

We had an energy audit and found that the can lights leak a pretty fair amount, no suprise there. The cans are "airtight" for use in attics with insulation. We have R49 blow in cellulose installed.

So I went into the attic with a can of foam and the lights are installed with spreaders that go from truss to truss. How to foam these in effectively is a mystery to me. Building a foam box around them would seem to reduce the amount of insulation and defeat some of the purpose.

So is there an effective way to seal on the living room side of the light effectively? I'm thinking a flexible stick to absolutely anything tape or maybe caulk with some sort of needle tip to get well into the very tight crevice between the can structure and the ceiling drywall.

What is the best way(s) to seal up these leaks?

Oh, and with Great Stuff, I like the window version for most everything. It stays more flexible so when the structure moves a little it doesn't allow leaks to develop like the other more rigid foam. Hey, might as well get the maximum benefit, right?