First off, is the mesh an absolute must in the front of the bonding pouch? Even if I leave the top open? Also..what size would it need to be for 2 gliders? And does it have to be sewn fleece, or can I tie the ends to make a no-sew pouch?

You should look on Suz website. She has instructions on how to make great no sew pouches and other items. (:

It's not a MUST to have a screen in a bonding pouch, I personally have a few without them and I zip the top and let them hang out for an hour or so. They're not air tight, the screen just allows for more ventilation. 9"W x 7"L is a good size, it allows you to easily put gliders in and take them out again.

As for it needing to be sewn, a sewn pouch will last longer, but here is a link to a page with instructions to make a no sew bonding pouch.

http://www.suzsugargliders.com/nosewbondingpouch.htm

If you're somewhere HOT, I would get pouches with mesh windows just to be on the safe side.

I would not use a no-sew bonding pouch to take gliders anywhere. I would worry too much that they would manage to get out. I think something sewn with a zipper is best.

I live in Georgia..so it is VERY warm here. I would feel better with the mesh honestly because the summers here easily get over 100. What sort of mesh do you use though? Cloth mesh or the plastic mesh?

I use this mesh for my pouches:

Mesh

Joann sells pet mesh/screen too!

If you're planning on sewing this yourself, are you familiar with the way glider things need to be sewn?

Luna spends most of the day asleep in my shirt or bra. She comes out once or twice to pee on my arm (sometimes poop a bit) give me a nuzzle and go right back to sleep. For a glider like her, I don't usually need a zipper. Some gliders are more curious though, and a zipper would be better. Starting out, you might want a zippered pouch to be able to put them in. That way if they get scared, you have somewhere dark to put them that they can't get out of. Before they're bonded to you, they may not run to you if they're scared or freaked out.

I bought my pouch, and it is sewn. I don't really know how to make a no-sew pouch. If you do sew one though, you need to be super careful that your stitches are small. If they stitches are too large, their little toes/claws could get stuck on them.