For me, much like you,I wear glasses and have a hard time sitting for long periods of time. As for a face mask I use one made by HS Strut, it's what they call a 3/4 mask. It has an opening for my eyes and that's it. It's pretty comfortable, keeps me hidden and keeps the bugs off too.
For a seat I use the small turkey seat sold in most sporting goods stores for turkey hunting. I've had mine a while and it has fixed legs, most today colapse. I find I can set a couple hours without getting too cramped, most time that's plenty long enough to get in and close the deal
Hope this helps