The small pools are killing almost any kind of bet.
In the Superfecta, for example, the most likely combos have about a 1 in 500 liklihood.
So (just as a 'for instance'), if the betting is proportional to the combo's liklihood, you get the following situation:
Pool $ bet on size high-probability combos 5,000 10 4,000 8 3,000 6 2,000 4 1,000 2
So, even a $1 bet on a more-likely finish can ripple the payoff. Is this acceptable?