I've noticed a difference between whey protein and plant protein....whey makes you extremely thirsty (dry mouth) afterwards. Plant doesn't. Well, at least it's been this of my experiences. I think I'll stick to plant protein for good.
What kind of plant protein are you using? I used soy protein for years before I decided on surgery, when I switched over to whey. I haven't experienced dry mouth, but I do know that I am satisfied longer with the whey protein.
I'm using VegaOne plant based protein. It's pretty good. I only took whey with the already made drinks and I don't think I'll be drinking them anymore. Trying to stay away from whey altogether.