I schedule my rests from about noon until 4, approximately.
We RD as much as we can and we really take advantage of EMH and FP. I do my best to get my FP for the morning so we can keeping getting new ones in the afternoon.
To maximize our park time I RD as much as possible and take advantage of EMH. Generally, I plan to be in a park from opening until about noon. Then we head back to resort for a few hours. Usually we are back at a park by 4, but if it's late EMH at MK we might stretch our break time longer. We make ADRs that don't cut into our preferred park hours. I don't count meal times as breaks, especially for TS, because everyone really has to be on their best behavior of the day while we're eating. I like to have lunch in the room where I can make a sandwich and put my feet up for a couple of hours! Bus rides only count as breaks if we're heading back to the resort. When we're taking a break, we're really relaxing.
I think the key to taking breaks without feeling like you're missing out, is to have a detailed plan in advance. I print out a park map, mark the attractions we want to do, and note the run time of all the shows. Then once I have my FPs, I make an itinerary for each park day and map out our route to eliminate backtracking. We don't follow it exactly, it's there so there is no guess work. If someone has a better idea in the park or we want to get on Buzz 3 times in a row, we do it. If half the group wants to stay back and swim in the afternoon, we split up. But I NEVER have any of those "what do you want to do" "I don't know, what do you want to do" conversations, because I always have a plan in my pocket. And if we're debating staying in bed or heading back later, I already know what might get missed.