This was a job that took longer than it should have done. This is the first part that doesn't fit properly. Vans sent an update to the plans instructing builders to elongate the mounting holes as necessary to get a good fit.
The water radiator has a solid mounting flange on the right (Picture 1) and a couple of brackets on the left. As manufactured the unit does not sit flush against the heather door ribs, and it is possible that the heater door when opened fouls the radiator vanes. That happened in my case. I ended up elongating all 5 mounting holes. And I had to file a bit off the bottom of the flange to get it to fit next to the cowl mount hinge. Picture 2.
Picture 3 is looking down from the top of the radiator onto the top heater door rib. I needed quite a large gap, maybe 1/8th inch for the door to swing freely.