Answers from ex-KO pitch player
Good post. Smart of you to recognize the cause behind your crash and burn: Inferior games, overbetting advantage, fatique. Add alcohol to the list and you have the famed Four Horsemen of Ruin.
Here's a few thoughts, hopefully a few others will chime in.
Departure point--wonging out--needn't be a consideration in single deck. Why would you? If the count goes negative, it can go very positive the next hand. Just bet minimum in negative and ride it out. Dropping out after you saw all four aces come out in the first round of SD was wise, but will also draw attention from the pit, particularly in higher stakes, or low stakes after they've watched you win for a while.
Same for DD. If a count goes very negative, I'll take a bathroom break on occasion, but more often I'll just ride it out. Sometimes we forget that we don't lose every hand in a negative count, sometimes we win half of them, or win a bunch in a row. One thing you might do to sharpen your game is expand your indices a little outside the I18 to include when not to split and double in negative counts. But playing through negative counts betting minimum at DD is not a very big blow to your expectation, not like it would be at 4 or 6D. It ends soon.
If I'm playing DD and there are other DD tables with spots open but the one I picked is giving the best pen, I'm not going to leave that table for another one, no matter how negative the count.
Another recommendation, practice and perfect a side-count of aces. It's very simple for SD and DD. SD you could do it right now (in your post, you already did!), DD takes about a half-hour of practice at the tables. Info on how to factor an ace side-count into standard KO abounds. I don't know how to do it for KO.
In term of number of hands, I too recall a sim that showed expectation dropping significantly at more than three hands for DD and SD. So I avoid casinos at peak hours, and will make a move to a table with one player if the table I'm at starts filling up. But if I've driven 90 minutes to a casino and my only option is to be the fifth hand at DD, I'll play it. Some of those players are going to drop out after a while. Another DD table that was full might get cleared. Watch the other tables.
It's never advisable to overbet the count. The one thing that has really stabilized my bankroll in the past three years has been to religiously base maximum bet on total bankroll; maximum bet being 1% of total bankroll is one way to do it (i.e. $5 table needs $5,000 bankroll to bet 1-10 units at SD/DD). It's tough to lose your bankroll doing that.
Unless playing head-to-head, in which case spreading to two hands offers no advantage over one (see Don S., "Blackjack Attack"), spreading to two hands where each is at 70%-75% of your single-hand maximum bet is advisable at upper positive counts. You gotta hang in there with that one. Sometimes you get killed.
Finally, as you get back into the flow of things, you might consider switching from KO when playing SD and DD. I switched to KO for all games when it came out, but now only use KO for 4D and 6D, and learned Zen for SD and DD. It depends on how much work you want to put into it, but a level-two system like Zen or Halves is a lot easier to play correctly during a SD session than 6D. I suspect--someone could corroborate--that even hi-lo with the proper factoring of aces is going to beat KO without an ace side-count, and hi-lo with an ace side-count isn't very tough when you only have to pay attention through one or two decks before you get to take a mental break.
SJ