Turns out the folks that make the S-5 clip now have a bracket for the delta rib type roofing. I got a few and tried them out this weekend on my well house roof. Their background is in the metal building industry, so they understand the challenges we face with metal roofing mounts.
The ProteaBracket is a well constructed, heavy gauge stainless bracket that is adjustable.
I bolted plated strut onto the bracket, then clipped the collector to the strut. They do have some test data for loading available from a third party testing lab.
The silicone rubber roof boot is from aztecwasher.com
just bolted lengths of vertical strut channel through the roof and used standard L brackets to connect the horizontal runs. There are already hundreds of screw penetrations on this style roof, a few more don't bother me. How many of those S-5 clips would it take to support 2400 pounds of panels?