I get nighttime dry mouth too - even “watering up” doesn’t stop it so I keep a glass of water handy and if I wake up, I swish some around to moisten things up and take a few small sips.
Tried the dry mouth remedies and they don’t work for beans - 30 minutes after using them, my mouth is dry again - funny how it only happens at night.
I’ll also get dry mouth when I’m walking briskly on a warm day, after I’ve been breathing through my mouth for a while. Generally not as bad as at night, though, because I notice it sooner.
You’re right about the remedies. They don’t work. My dentist gave me some sort of lozenge that I was supposed to tuck between my cheek and molars. First night I tried one, the damned thing came loose and about choked me to death.