Yeh from my experience (and im a Sev nut!) it goes like this...
Heros Efaciatus ...(Golds, Greens, Turqs, Reds) Average @ 9" max @ 12" in very large tanks, more bulky than the other species (fatness)
Heros Sp. Notatus ...(most are hybrids with Efaciatus) Average 9", never seen one bigger
Heros Severus ....Average @ 8", only ever seen a few and none bigger than this, tend to be slimmer in width and height and a slightly longer snout (probably for brooding eggs)
Heros Sp. Rotkeil ....max @ 8" usually average only 6", not as thick as Efaciatus, more suitable for your standard 4ft than the average Heros......any Rotkeil that is a hybrid with Green Efaciatus (the ones with the red fins) tend to get bigger from what i have read....a True Rotkeil should have a blue face, yellow fins, green body and a Red Neck.
Heros Sp. Appendiculatus ...unsure, only ever seen juvis in real life, i guess they are more like Rotkeils because of the similaritys (Appens. tend to be a dull version of the Rotkeil like the picture of the big guy i posted at the start of the thread)
my LFS is taking my surplus stuff, i might even keep 2 pairs of Rotties if all works out. (unless i find some Severus or true Notatus local!)
Can't wait till my babys arrive now!!!! my mates are rubbing there hands together to..to get hold of my prize sevs lol.