Sorry dude, didnt see this post

Eagle rods are fine, in a mondeo block (you can only use mondeo blocks for ZVHs). But, you need to remember you want a Focus type piston, if you have Eagle rods and a Mondeo piston, the combined rod and piston length will be altered and not work!

So get a Focus type piston. As for CR, thats up to you to decide what you want to run, and have the pistons machined and measured to suit. I'd imagine a piston with say an 8.2:1 CR in a Focus 16v head, would be about right, be in the 7.X range (without working it out) when using a 8v CVH head.

Where's Sketch with his CR Spreadsheet?