I just finished what I think is a good method to closeout the stabilizer trim slot, to help keep cold air from blowing into the tail cone and then forward to the back of your neck. I used "Easy-Cut Strip Brush", part number 7900T1 from McMaster-Carr. Using Hysol, on the inside of the access panels, I glued a piece of the plastic strip brush on each side of the slot so the brush tips meet on the centerline of the slot. When installed, the stabilizer tube travels up and down the slot, easily moving the brushes out of the way, but still closing in behind. Tried it out today on a 3 hour flight and it works well; less drafty in the cockpit.