Ahhh, I can hear DD' sighing now. $20 says he doesn't respond to this one!
Always play two hands if your risk criterion can handle it. This question has been answered ad nauseum (no offense).
However, I am assuming that your question is that your ROR can only handle a spread of $5-$50 at a 2D game or something like that, when should I spread to two hands?
OK, here's the deal. It doesn't matter what your count system is. By spreading to two hands instead of one, you can put down APPROXIMATELY 1.4 times as much money on the table and have the exact same standard deviation. So, for your KO max bet of $50, you could instead make two max bets of $35 each and the standard deviation per round would remain the same, but of course, the EV per round just went up by 1.4. So, what did that do to your SCORE? It increased it, correct?
The problem with non-true counted unbalanced systems like KO is that they are only absolutely accurate at the pivot. Sometimes you actually do not have the advantage at the key count (ie-late in the pack).
Why play two hands when negative EV?
1. Card eating effect.
2. Cover - nothing is more obvious (or irritating) than somebody who goes from one small hand to two big hands back to one hand, etc. You'll get the ploppies mad, won't look like the ploppies - which wouldn't matter so long as the pitstiffs don't care. Also, you'll be eating up hands and causing shuffle ups (especially if you're playing SD) if you do this.
Lek Tol
Anubis