Doubling on soft 19
Here is what I use:
Single deck: IRC = 0, Key = 2, Pivot = 4
A,8 v. 4 = Double at pivot (4)
A,8 v. 5 = Double at key (2)
A,8 v. 6 = Double at key (2)
Double deck: IRC = -4, Key = 1, Pivot = 4
A,8 v. 4 = Double at pivot (4)
A,8 v. 5 = Double at key (1)
A,8 v. 6 = Double at key (1)
Six deck: IRC = 6, Key = 22, Pivot = 30
A,8 v. 4 = Double at pivot (30)
A,8 v. 5 = Double at key (22)
A,8 v. 6 = Double at key (22)
NOTE: for single and double deck, I stick by the numbers. For 6 deck, I will modify my indicies according to the true count. While I don't really true count KO, I use Bootlegger's excellent chart for 6 deck to quasi-true count KO. Thus, if after 1 deck played I am equivalent to 22 (which is the "average" after 3 decks played), I will double accordingly on A,8 v. 5 or 6. However, with this being said, the opportunity really doesn't come up that often, so sticking with the above numbers should be fine.