The other benchmark of both the maple and blackberry flows are that they align with swarm cycles. I've heard of several swarms already this season due to the early maples and would expect without the normal spring lull before blackberries the swarm that urge will be compounded in the next few weeks. If you want to catch them before they do something you really need to be in there every 7-10 days right now.
This is the buildup from the swarm pictured above after about 12 days. The gap you see was left by the pollen/nectar they placed around the initial broodnest as the queen started laying eggs. Not to be slowed down she skipped over the cells that weren't empty and kept laying. Now that the food is used up from feeding the brood there is a hole or wave in the pattern. As those cells are cleaned up she will go back and fill them in.
This comb is more of the text book look for how honey, pollen and brood should lay out on a comb. Keep in mind this is a flipped view and the comb is actually upside down in the photo.
The below are couple photos from the overwintered Quickdraw hive.
You are seeing big drone cells at the bottom of a comb here. Notice how they point upwards and not down like a queen cell would. I get a lot of questions from new beekeepers that see these and think queen cells because they are big and at the bottom of the frame. Queen cells always point downward and would be even bigger than these!
Back to the bees,