Cubdriver

I'll echo all the other decent opinions that for private pilot candidates, night should be kept to the FAA required minimum hours. The student needs to see the visible (day) horizon to develop a sense of attitude awareness such as how the airplane looks while doing various air work maneuvers. Private pilot is not an instrument rating and I discourage night dual hours other than needed to meet minimum for the certificate.

Also, I agree a night solo signoff for a private pilot candidate is not a wise idea. Flying is brand new to this group. They need to do their instrument ticket before they fly at night solo. My understanding of the few hours of instrument training given to private pilots is something to provide an emergency instrument skill set until they get an instrument ticket. It is not adequate for night flying, which can easily turn into serious IFR flying.