Well, I just can't speak to the H-II or H-III option. I haven't heard that setup since 1980 and I just don't recall. I would sure love to hear that option again! Out of the 3 options discussed, the Academy beats the RC-xx boxes. The Hereseys would probably be better (?) but I think that space was 1 of the issues.
As far as adding a sub, BY ALL MEANS! I have a KSW-12, also. I listened to the system without a sub for years and when I finally added the KSW, I couldn't belive what I was missing. Keep it near the center though. They say that low freq. are omni but, I can tell right where the low end is coming from. It's a curse. So, I have a second sub coming. If it doesn't do what I expect, it will be for sale soon. (I don't think that will happen.)
I am really going to try to find someone with a Heresy to bring over. Now I'm intrigued!