Brian, the proper way is to check the boards with a moisture meter. In general, they will not acclimate stacked in a box, or even stacked tightly together, because wood needs to dry from the face out, not the ends. You want them all to be around 8%, give or take.
The proper way would be to stack and sticker the boards inside the house - with a gentle fan running on them and the HVAC system infull operation.
In particular, you want the HVAC to have been running for a few weeks prior to bringing the flooring in, so that the subfloor has equalized.
I just finished kiln drying 2500 sq ft of 5" red oak flooring that a guy purchased, had installed, and then ended up removing when it started shrinking. It was originally kiln dried in Michigan, but it had equalized to 14% while in transit and in storage at his new home (no AC running....).