Yes, just open the lid and
Yes, just open the lid and peek. I would probably wait until the temp was > 1000 deg F, since the glass isn’t going to move before then anyway (actually, it probably won’t start budging until 1100 or greater). Check every 5 or 10 minutes. Keep in mind that the kiln temp drops a little every time you peek, so you are slowing down progress .
If your kiln has a programmable controller, then it also has a “skip segment” function. For instance on a couple of my controllers you press the up arrow until you see SSeg (or something like that), then press the enter key. The kiln will move on to the next segment, which is probably your anneal.
Make sure you have an adequate annealing schedule to account for your differences in thickness. Also, make sure not to “rush things” by raising the temp too high — given that you have a single layer of glass in places, you want to make sure the glass bends, rather than stretches (if it stretches, it could get too thin and tear).
Jester’s Baubles Fused Glass Designs