I’m just trying to get a handle on queues for August, IF we manage to get to WDW. We normally stay for a longer period, but only go to the parks for a few hours - so pre-covid we’d RD a few lower-tier attractions with FP+ for the bigger ones, then leave. It makes for a more relaxing trip!
My question is if I put in, say, 6 attractions to a TP, and set the times for all day, will it tell me the best time to go during the day? Or will it just assume I want to start first thing?
What I’d ideally like is for it to say, for example, for these attractions you’re best off ignoring the park in the morning, arriving at 2 and then doing them. (I’m thinking of the current lull at the end of the day, though clearly fireworks may change all that.)
I’ve tried a couple of dummy TPs but they always start first thing - that might be because it’s the best thing to do, or it might be because that’s the default of the algorithm!
Have you tried putting in a large break? I did that in my plans and it tells me which to do in the morning and which to save for late afternoon/evening when I return after the break. Without the break it may assume you don’t want to sit around in the park for 6+ hours doing nothing just to minimize the wait.
You can put the start time and put your expected breaks if you would like. You can also click on each ride to see the expected wait time by the hour of the day. Those two things should help get you what u want.
Thanks - the breaks don’t really work since they’re not flexible enough - but the chart of predicted wait each hour for each ride gives me a pretty good idea. Bottom line is I think the wait times for the headliners are too long for me without FP+ or similar so I think even if a UK-US flight corridor does open, we may not go 
Also check out easywdw.com & thrillgeek.com
These, IMHO, are as good at documenting queue waits. This should give you multiple sources to figure out the best times to do what you want.
I think, regardless of ride or park, arriving at rope drop is the best time for every ride. The longer the park is open the more people are flowing in. Maybe some start to leave early afternoon, like us, to go hit the pool, but no better time than rope drop. I’d imagine there are stats out there somewhere, but my guess is the 1st hour of the park guest numbers would be significantly lower than the last hour of park guest numbers, especially with fireworks coming back.