yeah, it has to be hot.
seems to me you're really overcomplicating things for little or no benefit.
I have a hopback and used it several times b/c I was chilling with a Therminator/CFC chain and locking in aroma from flameout hops was tricky. Now that I have switched back to IC, I don't use the hopback anymore, and I frankly cannot tell the difference between the two - not that I did sidexside comparisons, but I don't notice anything missing, if you see what I mean.
Just my $.02