What is generally considered the most powerful system in terms of
- playing efficiency
- betting correlation
for 6 decks?
You can get with ace neutral systems if you mainly paly single and deeply dealt 2 deck games. An ace minus count will cover shoes too, where betting efficiency is more important than playing efficiency, and will be close if not as good as ace neutral counts in those single and deely dealt double deck games.
Think of a curve, for your edge versus the number of decks, where just about all counts travel up a logrythmic curve, which grows fast initially and starts to tapper off later. All the counts are about the same starting out, but the curve is chopped off into a tighter curve if you plot the power of the ace neutral counts.
The unbalanced systems only have 1/2 their potential playing gains if you use them in runnning count mode and limit your ability to use some advanced tactics later on. I recomend balanced systems instead.
Other than the above just pick the count that you can use error free. If that means you pick K-O over hi-lo or some other count that is just what works for you.
Best of Cards!
Thorp had an "ultimate betting count" in the first edition of Beat The Dealer which had 100% betting correlation. Griffin created a 180-level count with 70% PE in Theory Of Blackjack.
Neither counts are useable as a practical matter, or provide significant gain over the best level-1 counts except under excellent single-deck conditions.
