Since my floor is so dusty from the cleanup, I've wanted to wet mop it. However, if I do that, how long should I wait for the floor to dry before applying the CaCl test kits? Also, would the results get skewed if it is raining during the period in which the kits is applied?

Wait a couple days unless your really flooding it, then wait a week. Well....just do'nt flood it, damp mop. Must be tested in the living temp your accustomed to. Unless your an Eskimo, then you need to turn on the heat. Just follow the directions.

Thanks for the advice, Stephen. On a related note, the flooring manufacturer (Kahrs) recommends the following:

"Relative humidity at the job site must be, and remain, minimum 30%, maximum 60%. Temperature setting must be, and remain, within 15º F of normal operating range."

Assuming I do install according to these ambient conditions in the room, my concern is whether or not I will have to maintain these limits forever. If so, will I need to install whole-house humidity control systems to prevent cupping (during summer months) and/or separations (during winter months).

Yes, The manuf. suggested ranges are for the life of the floor. You will want to do what's necessary to keep within the range.

It's not that difficult to operate in the temp range. It's the rh thats difficult. It's a long story but prefinished manufactures want to protect their finish from checking first and foremost so there is no claim. I live out in the desert and see checked floors a lot but many of my clients who have used stand alone humidifiers do not seem to have a problem at all.

Stephen, do those customers that use the standalone humidifiers have a unit for each room where there is engineered wood. I have 800 sq ft of wood, will one standalone do the job in your experience?