We independently came up with @thesunneversets' idea, and found it a bit unsatisfying - it ends up being "Don Bell sometimes gets to use an extra Bang! card during his turn or can use a green bordered card immediately".
It's a fairly weak ability: since it's random, Don Bell can't plan for it and neither can any other player; even if he does get the chance, there's only a few "active" green cards for which this is useful in the first place (most of them are Missed! or Dodge equivalents); and players end up forgetting to use the power half the time anyway since he's the only character who regularly draws after the end of his turn.
The chance at an extra Bang is pretty good, but Doc Holiday already does that more reliably (and he pays any two cards instead of one Bang).
We decided that the interesting and unique part of his power was the interaction with green bordered cards, so we flat out changed his power to:
Don Bell may play green bordered cards from his hand as if they were brown bordered cards.
This lets him use the various green misses when he's being shot at, along with doing things like using a Buffalo Rifle as a lower-cost Springfield or a Pony Express as a Wells Fargo. He still can't use the Canteen as a holdout beer, though.
It gives Don Bell interesting decisions to make (do I discard some cards and keep this green in my hand where people don't know I have it, or do I play it so I can keep more cards in hand?), and it gives other players interesting decisions to make related to him (do I play this Pony Express, or do I keep it in my hand since he would want to Panic it from me and use it immediately? Do I take the Conestoga from the general store even though I don't really want it to deny him?)
Finally, from a design standpoint (because this matters to us for some reason) it also provides a certain symmetry with Delgado's ability to interact with blue cards.
