The HLLE study used A. Bahanius which are not really all that suited for aquarium use are notoriously skittish and difficult to acclimate. I also have never had HLLE issues when I used carbon, and ironically, I had an A. Bahanius that got some HLLE in a introduction/isolation tank that never had carbon on it. Back before good pellets and mysis added fatty acids and some vitamins and fish got HLLE all of the time, I could nurse fish with bad cases of HLLE back to as good of health as possible while using GAC. I respect Jay Hemdal and what he does, but that study was flawed, IMO.
Rinse it. Don't let it tumble and break down. This is pretty much GAC 101 even without any HLLE concerns.