The betting strategies for Hi-Opt II are in The Worlds Greatest Blackjack Book by Lance Humble. However, that book is fairly old. An excellent source for information of betting strategies (for any counting system) is Blackjack Attack by Don Schlesinger.
In short, your betting strategy will be based on the size of your bankroll, the game you are playing, the bet spread you want to use, and how much risk you are willing to accept. Schlesinger’s book covers all of this very well, and you can also find some information in the Card Counting forum in the thread
Free Counting Resources On Web (specifically the Gamemaster’s free card counting course).
-Sonny-