oK I didnt read the whole topic but this I wanted to say:
1)Don't loose your motivation because you cant find the right manufactering method.
It would be a pity to make a nice block like
this
into something like
this just because the first one is a bit harder to machine.
(it is very obvious that the first one would perform much better then the 2nd)
2)about the exact location of the core (in reference to the mounting holes) you'll find anything you need here
http://forums.procooling.com/vbb/showthread.php?t=8412
3)I wonder why everyone always wants his water injected in the shape of a circle, when the core is rectangular. What do you think of my "adapter" idea (upper part of the block adapts the round fitting (from the water inlet) to a rectangular opening (to inject the water on the core). More info in this topic:
http://forums.procooling.com/vbb/showthread.php?t=8380 (note 2 first pictures)