Good luck, you won't believe how much fun it is to have an OB hive around. I have been building them all summer. They are not difficult, just don't expect the first one to be perfect and you will be fine. I have been using one all summer as well and I have not had trouble with the glass in the grove. I use plexi-glass instead of real glass and I am also in mine about once every two weeks or so. Maybe they are not getting enough time to really propolis it in. I could see where it could be trouble. But I have not had significant trouble getting the glass to slide out.
Would be worth looking into the pieces that Micheal describes though, I could see that might work really well also.