Let me see if I can help at all for porosity.

Low - takes a long time to dry (naked hair, no product)
High - dries quickly

Low - hair doesn't wet easily
High - wets easily, quickly soaks up water and product

Low - when you run your fingers up a strand, it feels smooth (similar to when you run it down a strand), can squeak will you run fingers up a strand
High - when you run your fingers up a strand, it feels rough

The amount of time it takes your hair to dry can also be affected by density. Damaged hair also usually has high porosity. Low porosity is also typically shiny and reflects light well. High porosity tends to be duller.

You may also want to try clipping while plopping. It keeps the roots lifted but still gets the benefit of your hair being upside down.

I have a similar problem where my hair looks awesome out of the plop and then the 2b-2c waves fall back into being 2A as them dry. I attribute most of it to length of my hair pulling out the waves. I did just buy some mousse that I plan on trying for the first time since being CG. I'll let you know if it works!

Wave Pattern: 2A
Hair Properties: Normal/Low Porosity, Medium Density, Medium Texture w/Fine Straight Underlayer
Co-wash: Suave Naturals, Cure Care
Low-poo: Renpure Brazilian Keratin
Rinse Out & Leave In: Tresemme Naturals
Gel: LA Looks Mega Mega Hold Gel, Garnier Fructis Spray Gel