This sounds like a fun project! I agree to use the cut a way stabilizer for the fabric. You may want to try the spray solution on a piece of scrap fabric first to make sure it doesn't change the color of the fabric.
How dense is the EMB design?
I am starting a project to EMB on duck cloth and confirmed with the LQS to use cut-away for the stabilizer Generally, I use a microtex needle for machine EMB. I will also use a topping so the stitches don't sink into the fabric.
Scroll down on this 101 How-to page for outdoor fabrics. I included the whole page as there is great info on other fabrics too. Hope that helps!
https://www.emblibrary.com/EL/ELProj...ory=Fabrics101
Looking forward to seeing your progress! Great idea!