There's a lot of different info out there about suggested time between nitro coats. Minimum time seems to be about 20 minutes, maximum time 60 minutes. Normally 3 coats a day maximum, then let it dry and harden overnight. Very important to let the finish harden before you attempt to polish it. 1 week is the bare minimum, but 2 is more normal and 3 would ensure that it's ready. High humidity slows drying times, so if that's the case, go with the longer drying times. Too hot a day (say 35°C+) can be a problem as the spray can dry in the air and go on rather powdery. Too cold (generally below 14°C), or too humid when spraying, and moisture can/will get trapped under the finish and turn it misty. So it's best to spray with the temperature in the twenties and with reasonable levels of humidity (if possible).

Note that Nitro is hazardous to health, and you need to buy a vapour mask and should cover up as much as possible to stop it getting onto your skin - wear rubber gloves or disposable latex or vinyl ones. If you can smell the spray with the mask on, then it's either not seated well enough on your face, or the carbon filter is all used up and it needs replacing. The vapour is also explosive, so use a well ventilated area and no smoking or sparks. The finish touch dries in about 5 minutes, so if you are spraying in a garage (to avoid as much dust as possible), then I'd spray, shut the outside door for 5 minutes, then open the door again for ventilation to disperse the fumes. Any door to inside the house should remain closed as you don't want the fumes inside.

The StewMac/Dan Erlewine Guitar Finishing book is a very good reference book, but it does spend a lot of time on talking about how to match various classic (mainly Gibson and Fender) guitar finishes. A lot of the information is already available on the StewMac website - you just have to look round for it.