Is Gortex the same as GorE-tex?
Just don't forget all waterproof materials will make you feel like a boil in the bag .
Plus if you kneel down you will be placing a smallish area under a lot of pressure and most will let water in at that area.
Material with a high static head reading will be better than cheaper fabrics.
And don't forget , the army now call their waterproofs MVP fabrics . And not all of those MVP fabrics are Gore-tex
Some army garments were made with porrelle fabric by a company near Glasgow. The troops hated and Gore-tex was used by the company.
That was years ago. Not sure if they still use Gore-tex. The garments the troops call " guchi" ( sas and some others) are still Gore-tex.
I know the above due a friend being in the lab at W.L Gore and his father is in the MOD sales department in W.L Gore