Tom,
As far as how to assemble the array IE whether it's made of individual cups, milled out of a solid block or as some have suggested milled from a casting, that should be left to the implementor. What we need now is a solid foundation to build upon. If you can show how you will be able to  drive this array, we can figure a way to build it.
Stan and I have had some experience building patches on S band and we believe we can build C band patches. It's obvious that putting the patches in a hex array gets more for the same amount of real estate and therefore gets you more gain. Do you think you can come up with a way to drive a hex array or not is the question. It would seem be be more symmetrical around the Z axis and therefore have less spin modulation.

Fred Parker has been experimenting with castings for an S band array. His casting is still rough but has promise. It has 1/2 inch under the array to put the amplifiers and phasing harness. The array looks like this. We made a test casting. It weighs .8 Kg.
We will put some patches in and see how they work.