The standard protocol is rope drop, waiting until the end of the night, or maybe going during a party time.
However, I would not worry too much about it. I am in a similar boat where I could not get a 7DMT fast pass at my 60 day mark (at 7am!) but despite my initial disappointment, it is not too bad if you look at the big picture.
7DMT, Space Mountain, Splash Mountain, Peter Pan, BTMR, and maybe Enchanted Tales all are priorities. So you would need to stand in a standby line for some of the top rides. You still save time on three rides no matter what. Sure 7DMT is usually longer, but the Mountains and Peter Pan routinely hit 45-60 min wait times anyways. Even if 7DMT is a 70 min wait time you still save time on the other rides. 7DMT from what I read has a good standby interactive line.
My fuzzy math: say 7DMT is a 70 min wait and instead of 7DMT I picked Space Mountain with say a 45 min wait around the same time. Factoring in maybe a 5-10 min wait for the fastpass line in an ideal setting, I am only "losing" 15 mins (70 minus 10 minus 45) by not getting 7DMT.
For what it is worth, I plan on going rope drop on my MK day but if it is too long, elect to do all the walk on rides while everyone is in line for 7DMT and then suck it up and wait for 7DMT later. I am blessed with fast passes for Space Mountain, Splash Mountain, and Peter Pan so overall I feel that I am still being efficient with my time.
Hope this helps and enjoy your trip! I know I will mine, no matter what when I get to ride 7DMT. It is my first trip and I need to keep reminding myself while my fast passes and dining reservations are not "ideal" at least for disboard standards, I am still going to have a magical time.