This is my design. But I'm going to eliminate the outer channels. (Had a friend render it from my autocad deisgn)
I'm going to alter the deisgn, and stagger drill (because I'm going this with a drill press) the center channel. By that, I mean make every hole that I drill about .025 inches of center of the channel line. This will improve heat transfer by causing some micro-swirling (hopefully) in every hole. But, because they are only a small but off the center line, there won't be that much resistance (hopefully)....