Surface area is a primary determinant of evaporation losses - at room temperature. Those losses are pretty negligible over the hour or so you're boiling the wort and chilling it. Of far greater importance when boiling the wort is the heat input. Pretty simple physics - the more heat energy you supply, the greater volume of water will make the leap from liquid to gas. If you're going to use the same heat source following the same practice, expect your evaporation/boiling losses to be nearly the same regardless of which brew tun you use.
On deck: a clone of Carolina Beer Co's Rye Stout, clone of Breckenridge's Vanilla Porter,
Secondary: Dortmunder, Hopweizen
Keg Conditioning: Dunkelweizen, Roggenbier, Okto, Ord. Bitter
On tap: Alt, Hefeweizen, Cigar City Maduro clone, Mild
Bottled: Mead, Quad Rajet, Granola Bar Braggot
Too much of everything is just enough.
- J. Garcia