It really depends on how much moisture is in the air. If it is at a dry place like Arizona, you can wipe it off right away.
However, here in the NW, more time is needed, and so I usually do the whole car, and take it off starting from where it went on first. Seemed to work fine.
The cure time should be at least 24 hours, or else you will still be removing some of the wax on the first layer. I personally would just do a layer a week, since weekly wash tend to weaken NXT.