In the last part of the mating act the rooster hops off. His job is done. The hen stands up, fluffs up, and shakes. This fluffy shake moves the sperm to a special container near where the egg starts its journey through her internal egg making factory. That egg can only be fertilized during the first few moments of its internal journey.
That sperm can remain viable there anywhere from a week and a half until a lot longer. It's going to vary by hen and rooster how long it does remain viable. For most it's in the range of two and a half weeks but on occasions it has gone over 4 weeks. Some breeders hold a hen away from an undesirable rooster for three weeks before they collect hatching eggs from the new rooster but others wait four weeks. It depends on how sure they want to be.
I don't know how many chicks you actually want. You already have 2 dozen eggs in incubators. If you are desperate to hatch as many as possible you can continue collection for four more weeks. Most of those later ones won't hatch but you could get lucky on a few. I think you can collect eggs for another two weeks and have a reasonable expectation that most of those will hatch.
Unless you know what you are doing I would not do a staggered hatch in one incubator. All the eggs in one incubator need to start at the same time. You can use one incubator to incubate and another solely as a hatcher. If you need help with the details let me know and we can discuss.