I completely understand your view as I am finding that the older I get and the bigger the fish get I own the more space I believe they should be given. Thank you for your input Chicx, I appreciate it comrade.My idea of what is fair and the general community's is quite different, and I try to not impose my personal opinions onto the community by answering questions like this that could be viewed as authoritative.
That being said, FOR ME, when dealing with adult specimens of either of those species, I would want at least an 8x3 footprint.
They'd probably be fine in smaller, but that's what *I* would do.