Good luck!
And to temper the responses above about the length of time you can hold eggs... well, yes you CAN hold eggs for 7-10 days. However, with shipped eggs you must figure that any seller worth their salt will be giving you eggs less than 4 days old at shipping. They spend 2, maybe 3 days in transit. So the oldest they SHOULD get to you is 7 days, the youngest being 2 days if the eggs are picked in from being laid that morning (not picked in that day from being laid the night before) and they get to the PO in time to be shipped that day. The average age, I would say, is probably 4 days- eggs laid a day or two before shipping (or laid one day and brought to the PO too late to go out that day).
However, depending on where you get your eggs from, there's always a chance that people are giving you eggs OLDER than 4 days at the time of sending (for instance, people with only a few hens).
So yes, eggs can be 7-10 days for setting... but you may not be able to hold onto them for that long if they've been shipped. And in this heat, I wouldn't hold them long at all before incubation because they can, have, and do start incubation in the shipping box.