I actually have no idea what Hypo is. I've often read its name, but never bothered to work out what it is.
I tend to run heaps of fresh water over my negs. Not heaps in terms of volume, nor time. I'll put at least 10 of the Jobo bottles (600ml?) through the system, leaving them in for a minute or so each flush.
I figure that there is more benefit in exchanging/refreshing the wash more frequently, rather than letting the film roll around in left over chemicals. No scientific backup for this, just shooing from the hip.
One final thing that I do: I squirt Photoflo over the hanging film using an atomiser. I don't like to potentially contaminate my tanks with this stuff, based on annecdotal reports of it being difficult to completely clean off/out.