Hey Bbqjo,
The starting material I used was (smokable) dry.
IDK like 30%-40% moisture content.
It will extract out of any oil bearing plant material.
I am not sure about garden herbs but, if they contain oil, yes it will.
This concept of heating & pressing has been used for a long time to extract things like Olive oil & on many kinds of oil bearing seeds such as cotton seed & sunflower.
I believe the term rosin comes from or refers to heat pressing the rosin out of pine trees.
Yes, They are for sale & I have sold a few.
If you (or anyone) wanted to copy this idea (for personal use) I would not come lookin' for ya.
I'd love to see it! Just give it props.