Ah, do you know the foam density? Great Stuff isn't very good, so I'm purchasing some two part pour 8lb density foam.
Ah one last question again, do you think r11, r290, r23, r1150 might be a plausible creation? One more HX added then your design. Most likely 9' capillary lines. So r11/r290 condensing r23, r23 condensing r1150. I know its not straight like that, as the first r1150 to condense will most likely be liquid or saturation in r23, and thus help more r1150 condense. But in our systems colder is better, and ethylene is readily available and used in cascade systems of ours.