You could use Red pitch for a medium to set you reppouse in or maybe Black pitch but it is very stiff. I used a small set hammer to flatten things out. If you look at Gene Olson's web site you will see some first class copper work and get some ideas for how to do big surfaces. I like your work. Very nice even if there are a few wrinkles.
Here is a link to some of Gene's work
King Porkunkhamun I ( 145 - 182 BBQ) - a raised vessel . Enjoy
