It really depends.
I'll use Magic Kingdom as the example.
So for Magic Kingdom, you basically have "tiers" of rides and attractions.
Tier 1: New or immensely popular rides - These will have huge wait times from the time the park opens until it closes. You need a FP+ for these attractions.
- 7DMT
- Anna and Elsa
Tier 2: The Main Rides - These are the most popular rides in the park. You can get on at a reduced wait time during EMHs but they can get up to 60-90 or even 120+ minutes when the park is busy.
- Space Mountain
- Thunder Mountain
- Splash Mountain
Tier 3: The classics - These rides have been around a while and have a cult following. You can walk on the rides during EMHs but will wait about 60 minutes when the park is busy.
- Peter Pan
- Pirates of the Caribbean
- Winnie the Pooh
- Haunted Mansion
- Dumbo
- Buzz Lightyear
Tier 4: Hit or Miss - if the park is crowded and there are huge wait times, these are the rides that will have a high wait time due to guest overflow. They're great rides, don't get me wrong, but don't normally see long wait times
- Teacups
- Small World
- Astro Orbiter
- People Mover
- Barn Stormer
I'm not sure how tall your boys are, and therefore, I can only speak from personal experience.
We go to MK every year for Xmas. There's a morning EMH and we always try and get to the park starting at 7am but never make it in time. We get there by 7:30am for the last half hour.
I'd recommend a FP+ for 7DMT. Even though we arrived for morning EMH, the wait time was still about 90 minutes! The only way you're going to get on the ride without waiting that long is with a FP+. Plain and simple.
I doubt your boys will want to see Anna and Elsa (maybe they will?) But I'd recommend selecting the rest of your FP+ from Tier 2.
When we arrive for the last half hour, we'll go on the rides from tier 2 and 3 that we didn't get FP+ for. So for last year, we did a FP+ for Thunder Mountain, Buzz Lightyear and Peter Pan (we had a FP+ for 7DMT a few days later.) When we first arrived at the park, we walked over to Space Mountain. It was a 20-minute wait. By the time we finished on Space Mountain, the park was open to the public. We walked over to Adventureland and went on Jungle Cruise. The wait time was already at 30 minutes, but anything below 45 is pretty good for Jungle Cruise.
After, we grabbed a QS breakfast. After breakfast we redeemed jumped on Small World, which was 20 minutes, followed by Haunted Mansion, which was 10 minutes (somehow.)
By now, it's around 11am and the park is starting to get packed. Ride wait times are creeping up pretty quick. Space Mountain is at 120 minutes, Thunder is 90 minutes. We have a FP+ for Thunder, so we redeem that. After Thunder Mountain we grab lunch. Then, we redeem our FP+ for Buzz. Buzz is around 60 minutes. After Buzz we watch the castle show and a parade. We redeem a FP+ for Peter Pan and we leave the park for the rest of the afternoon.
We leave in the afternoon and take a break before dinner. You may do this as well and give your boys a rest.
So some cliff notes (haha)
- Try and get a FP+ for 7DMT
- Tackle the Tier 2 and 3 rides during EMH and early in the day
- It doesn't really get packed until 10am or 11am.
- Set your FP+ for the afternoon. That's when the park will be most crowded. Get the most popular FP+s in the afternoon and tackle the other rides in the early morning.
Now for DHS and EPCOT and AK, where they ACTUALLY tier the FP+ selections, there's a lot more strategy involved.