1/4" thick copper stock, block layouts

I'm really close to having my first block made on a CNC
Problem is comming up with a design that will work good with 1/4" thick copper base. I know, i should have gotten thicker stuff, but this was all I could find, and I already have it, so that's what I'm using. I've thought of a few things, had a couple suggestions emailed to me, and I'm considering the design that JFettig posted HERE (the one with the rounded turns)
I need thoughts on what some of you think would be a good high-flow block design for a setup with 1/2" tubing, a 462gph pump (RIO 1700) and the heater core from a '69 Camero (1/2" barbs)

If your using CNC, make the block 1/2" thick with two halves. Cut the pattern in one then the mirror of that design in the other then bolt/solder them together.

I actually like that idea because if you get screwin barbs, it will have more threads in the top to hold it in.