By heavy cloth I was referring to the 6 ounce cloth.

If you intend to remove the foam after glassing, I would recommend a third layer of the heavy cloth.

Removing the raw foam by whatever means will leave an extremely rough surface on the inside of the fiberglass hull because the epoxy will absorb into the surface of the porous foam.

To minimize this, you will need to provide a surface on the foam that is extremely smooth that fills in the porousness so that the resin does not soak into the foam. I have never done that myself so hopefully there are some videos available that can guide you.