We always order 15 minutes before we want to eat, but I don't plan out much in the parks these days. We go with the flow.
I will say, don't count out TS. You can find reservations for nearly everything the night before, it seems. Last week, I had my choice of BOG, Chef Mickey, Topolino, and CRT for breakfast the night before. Check tonight beginning around 9pm and look at the openings that pop up for tomorrow. So if TS is important to you, just check the app periodically especially the day or two before.
(on Thanksgiving Day, we got a 6pm dinner at Beaches and Cream! So day of, popular spots open up on crowded days, too)