I don't have a password on Cachin's site, so I am posting a response
here.
Fixed Odds Betting
Many intelligent and educated people have already adressed this
problem. If you google "parimutuel betting professor",
you will get a lot of hits. Eg: "Efficiency Characteristics
of a Parimutuel Market".
Fixed odds work out better for fixed probability events. Like
if the state gives you a 500 to 1 payoff on a 1 in 1000 chance
daily number. 
Jai-alai is not like that. No one knows the true probability of
any given game. Tiger, Factor X, Steve Skiena, and others, can
all use a formula based on past peformance. But their formulas
have obvious limitations.
If I am there in person, and my observations and judgement say
that their selections are in poor form tonight, or some lesser
player is on fire, I will have a very different opinion on the
correct odds for that game.
Point is, since the true probablity of a game cannot be known,
it is not practical to use fixed odds.
Anyway, if you spend a little time reading up on what the experts
say about parimutuel betting, you will learn a lot.
Jai-alai is a Numbers Game
You have posted this many times, but never explained what you
mean. What is a NUMBERS GAME?
Obviously, the spectacular 7 scoring system produces a bias toward
certain numbers. But if the weakest team is in post 5, you are
only going to see a 524 occur once out of a thousand times or
so.
Jai-alai is a player's game with a strong bias toward certain
numbers.
According to jai-alai theory, the most favorable posts are 1 and
2, which each have a 1 in about 6.2 chance of winning. And yet
if you look at Perry's Picks, he is doing much better than that,
about 1 in 4.25. Obviously he understand which players are better
than others.
A jai-alai expert who has good opinions on the class and current
form of all the players, AND understands the bias of the scoring
sytem, will DESTROY anybody who says "Jai-alai is a numbers
game".
