Thank you for your replies!
I am actually trying to schedule now - I can see through April the latest, there are almost no appointments other than @ 8 am. That is the problem for me because I am not a morning person. 7 months in advance - and almost all good spots are taken!!! My husband took GMAT 2 years ago (in October) and he said he had no problem finding a good spot much less than 7 months in advance. Does this mean that more and more people are thinking about MBA, or there is some kind of seasonality in taking GMAT?
So I found one good spot at 11 am, which is a perfect time for my brain to wake up

and it's Wednesday, and it kind of makes sense for me that by the middle of the week a body (my body) sort of functions better, so maybe I am going to take it. I also thought before that Monday was the best day, but only because I don't have to take days off work.
Anyway, thank you for the tips!