Many people use these terms, and doing search gets plenty of hits... but no definitions.  I've got some fabrication questions.  Please help...

1. I'm stipping up the hull.  According to the scantling, it says I'm to fill the opening gaps between strips with Epoxy Grout.  Is that simply epoxy mixed with say... saw dust, micro balloons or something else?
2. And to fair the hull, Bog is mentioned.  Because its pink, I'm taking a wild guess that is Bondo used on car bodies.  Is that right or is it something else?
3. It would seem prudent to sand the hull as fair as possible before applying the cloth/epoxy layers.  I note in all the photos, that you are applying the bog on top of the cloth/epoxy.  Any particular reason for not doing it between the wood and cloth/epoxy?  Does it make a weak bonding surface or something?
4. For strip planking a small kayak, I needed to do 3 coats of epoxy on the wood before applying the cloth.  Is that still the recommended method for something this large?

Thanks,

Dennis