Thanks guys for the comments and suggestions. This was only a quick experiment to get an idea of how the slime looks/works. I used real life reference from my house, yard, shed etc. to get an idea of what it should look like.
As for adding a gloss to it, it might be OK for wet areas say near a stream. But by looking at the stuff around my house, it is matt / flat and is not wet or glossy. Keep in mind that like everything else this also varies.
I am working on a half track that will be getting some of this slime green weathering, and also a car model, so this was just playing around. I will spend more time when it comes to the actual model that receives the slime.
Thanks again for the feedback, much appreciated.
scratchmod