NIEN!
AS i have said a MILLION TIMES OPTI SEAL IS FINE OVER NUBA.
YES APPLY OPTI SEAL OVER NATTYS RED, it will seal in the Nattys look for about 10-12 weeks no problems. It wont change the looks hardly at all.
No need to mess about with less looks in the winter, use PS, use what ever you want and top with OPTI SEAL!
I should a do a sticky on Opti Seal!
As far as waiting goes, i have not tried it with Nattys Red but with PS you want to wait about 30 mins or so to make sure it has time to "air" my choice of words. LOL. But just a period for it cool off so there nothing to be expelled from the nuba before you seal it in.
Geoff