i find that using a roller to apply fill coats helps get a smooth/consistent application.

that said, a roller will leave bubbles so you will need to tip it out.  i use a yellow plastic squeegee for this.

how thick?  only as thick as the width of the cloth.  basically you will sand it to a smooth finish....and when you do that you do not want to be cutting into the cloth.  but its not like you need a milimeter on top of the cloth or any particular 'thickness' other than avoiding cutting into the cloth.

fill coats often go on a bit easier if after the first fill coat you take off the high-spots with 100 grit paper.

in the shop tips section of the website....they explain this:  http://www.clcboats.com/shoptips/epoxy_and_fiberglass/fiberglass_weave_epoxy.html

i would recommend reading this whole section....it is pretty useful.

Howard,

Thanks for your response and for the link.  I went out and sanded the hull with 80 grit, then 120 grit and got rid of pretty much all of the high spots.  The end result was an almost uniformly white hull, especially on the sides.  I plan to glass the deck and then do the final sanding of the sides and bottom after I've feathered the sides.  It looks and feels much better now.  

The article was very helpful, especially the part about not really needing a very thick coat of epoxy on the hull.  I don't plan to be running it up onto rock and barnacle crusted beaches any time soon...

Gero

   Fill coats should be applied with a roller, when trying to build up the epoxy and not have sags use a dry roller behind the roller your using to apply.

Coat about 4-6 ft then get the dry roller and go over it to pick up any excessive epoxy that piled in a hole as the wet roller went over or behind a ridge (the center line of the deck).