I think it would be interesting to try using the more complex Bennie rules listed in "Deadlands Reloaded". Here they are for your perusal. Let me know what you think.
At the start of the campaign, place 20 white, 10 red, and 5 blue, and 1 gold poker chip in a bag. This is the fate pot. Any time a player earns a bennie, the GM draws at random from the bag. The GM does the same for his Bennies.
Fate chips come in 4 different colors, but regardless all of them allow you to make a Vigor check soak damage and remove Shaken conditions as normal.
All Fate Chips go back into the pot at the end of an adventure (there's an exception, listed below).
WHITE: white fate chips act just like regular Bennies, and can be used for all the same things that regular Bennies can be used for.
RED: In addition to their use as regular Bennies, red fate chips can instead be used to roll an additional d6 and add it to your result (this die can ace as usual). The downside to this is that whenever you use a red chip this way, the GM gets a draw from the fate pot. The GM counts these as fate chips (they act like regular Bennies).
BLUE: this chip acts just like a red fate chip, except that the GM does not get a draw from the fate pot when you make use of its special function. The GM can use this sort of chip to roll a d6 and add it just like players can.
GOLD: there are very few gold chips in the pot. One goes in at the start of the campaign. One goes in each time the party defeats a major threat. And one goes in each time the characters gain an experience level (go from Novice to Experienced, for example). Gold chips can be used like a regular bennie (though why you would want to is beyond me) or may be used in one of two additional ways. First, they may be used like a blue chip, and in addition give a +2 to the roll. Second, they may be used to allow a reroll of things that cannot normally be rerolled — damage, rolls on a table, malfunction checks, etc. Once they are used, Gold chips are not returned to the pot. If the GM draws a gold chip, he or she should put it back and draw again.