Here's a comparison of the left & right ends of the damaged evaporator (Part #123 830 14 58, I believe intended to fit a Seimens housing) vs the left & right ends of my old evaporator (Part number not known - can't find a stamping and the label is long gone, out of a Behr housing).
Note the 3 crimped tubes on the damaged evaporator. It looks like the evaporator is designed to be parallel in 5 circuits. Meaning that the refrigerant is split into 5 paths, then each path loops through the coil in 3 loops (so 6 passes total per loop, 3 in each direction) making for a total flow length of ~30x the length of the evaporator. Those 3 tubes are all on one circuit, so assuming that they are 100% blocked (not realistic) I would be losing 20% cooling capacity.
Sorry that the pictures aren't all taken from the same angles.
I didn't get a great picture of it, but on the old evaporator there are 2 spots that might be leaks where the 180 degree bends are brazed to the long loops. I didn't bother pressure testing or thoroughly cleaning the old one yet, since I'm hoping not to have to reuse it.
Edit: Looks like my new evaporator should get here tomorrow. Here's hoping it's not damaged. I will get some direct comparison photos and try to fit it once it arrives.
