How I measure Marine Tex...
I use a piece of heavy cardboard, and I lay down a strip with the one part mixture, then with the five part mixture, I lay down five more strips, just like the first one, right next to the first one, Then I use a putty knife to mix it all together. You kinda have to guess, as to how much you are gonna need.
This has worked well for me, and it has always cured hard as a rock..
it's NOT easy stuff to try to pour and measure, but this method works well.
HARRY