Here's the follow up from my previous posts. I did the "tighten until it stops leaking" method proposed by Nouvolo and will list out these steps for other customers. I believe the risk of warping the cold plate needs to be included as a warning in the instructions for the current version of this product.
1. Loosely assemble the cold plate to the acrylic block. Twirl the hex key with your fingers until tight, but don't attempt to snug.
2. Setup the
leak test and attempt to build pressure.
3. Tighten the screws in increments and leak test between each tightening.
4. Once it stops leaking, snug the screws. I went about 180 degrees on each screw. Began observing warping around 360.
5. Take a
straight edge and check that your cold plate isn't
warping.
I opened an
old cpu block to show why the warping cold plate caught me by surprise. This block is designed to properly compress the O-ring when the mating surfaces are contacting, therefore it is not possible to over-compress the O-ring or noticeably warp the plate.
No doubt there are design constraints I haven't considered leading to the Nouvolo design being what it is. I'm still grateful for Nouvolo providing this cpu pump block as an option for sff enthusiasts and I hope this post is received as constructive criticism.
Edit: updated
imgur album with explanation of issue
