[tartuffe]

I don't think I would worry with pulling that inner skin out. What you see is woven roving. Basically just a very heavy-duty fiberglass.

If I wanted to bond those 2 layers together I would sand the top 4 inches of the inner layer with a heavy grit sand paper or even a grinder. You want to sand it so that the inner layer is paper thin where it meets the roving and full depth 4" away, so sanded at an angle. Use a putty knife and smear some thickened resin over the roving to squish it into the holes. Next I would roll a thin coat of resin over the sanded portion and then overlap the smeared resin and sanded/coated portion of the inner layer with a layer of 17 oz mat. I would then finish wetting out the piece of 17 oz cloth and then roll the whole thing with a metal roller. Once cured out sand the whole thing smooth.

Also youtube has alot of good videos to see different ways to approach things. Gotta watch a few as there are several that deliver some sub-standard advice.