re: Which is the correct resin to use?

Dave you were correct. already got a response from System3 folks.

George

 The type of epoxy will depend on the depth of your application:

 
Here are some helpful articles on why you want different epoxies for different depths of application:
Why did my epoxy resin mix get hot?
Why Do Mirrorcast™ and Rivercast™ Cure so Slowly?

Before pouring the epoxy you will want to brush on a thin coat of epoxy to seal the wood. Sealing the wood before pouring will prevent air from escaping the wood and forming bubbles.
How can I Avoid or Remove Bubbles in an Epoxy Application?
 
If you have any further questions feel free to ask and thanks for your interest in System Three. 

Nathan, you were correct about depth, now we know the stages to use.

Pretty cool, got an answer to my question, and some tips along with it.