I've been lurking for a while on this forum after watching Sara Adam's video on making double tissue and failing miserably. The result: krinkles and air bubbles galore no matter how careful I was. I experimented with different brushes, MC consistencies, wetting the glass, bottom sheet first, etc.. The air bubbles I could usually get rid of, but the krinkles were fatal. So I finally came up with the following method, hopefully it will be helpful to some of you who have been having similar problems

1) Get a piece of 1" diameter PVC long enough to wrap the tissue paper around.
2) Align the two sheets and wrap them around the PVC
3) Gradually work the tissue paper tighter and tighter around the PVC by twisting in the direction that it's wrapped, working your hands from the inside out to get as much air out as possible. Keep going until it's as tight as possible. Do this carefully to avoid creating any wrinkles
4) Tape the middle of the free edge to your glass
5) Using your brush coat the area of the glass where the paper will lay, with MC.
6) While pressing down hard on the ends of the PVC, slowly unroll the paper across the MC allowing time for the paper to soak up the MC under the roller.
7) With any luck the paper should unroll without any krinkles and minimal air bubbles.

9) Let dry.
Please let me know if this works for any of you!