Heh, I chose Right to Bear Arms, but it didn't really matter, since my dragoons and soldiers beat the king's forces to a pulp in forested hills and such.
It seems to me that it doesn't really matter what kind of choices you make with your constitution anyway:
Right to Bear Arms vs. Controlled Arms - +1 colonist Strength vs. +50% Liberty Bell production - If you need the colonists to protect themselves, you seem to have failed (at least I can't see why you'd give your colonies up freely o_O). Controlled Arms, well, I can't see why you need the Liberty Bells, since there's no Foreign Intervention in Civ4Col. The only thing you'd need those for is to boost your rebel sentiment bonus, but I don't think that's going to change significantly during the few turns of war of independence...
Monarchy vs. Elections - Trade with Europe or 100% Liberty Bell production - okay, so you can trade with Europe. So what? You can't really ship anything there (cause your coast is full of Man-o-Wars), and you need all your colonists to defend your colonies (Except the ones breeding horses and making weapons). You don't really need the liberty bell production, since there's nothing to accomplish (No foreign intervention in Civ4Col), except maybe to boost the "rebel sentiment" bonus you get a bit.
Manifest Destiny vs. Native Rights - Manifest Destiny is absolutely redudant - by the time your colonies are rebellious enough, the indians have "donated" their camps to you anyway (Or you have razed them

) and you really shouldn't be at war with any other factions than your mother country at this point. Native rights - well, okay, you MIGHT get some indian factions on your side but I haven't seen them do ANYTHING. It'd be nice to see Monty's mounted and armed braves to surprise the king's forces, but... bleh.
Slavery vs. All Men are Free - +25% to resource harvesting or +2 population in all cities - All Men are Free ABSOLUTELY wins. I can't see why anyone would pick slavery, since you really need colonists and
fast to fight. With 5 settlements, that's 10 people - 10 dragoons more.
Separation of Church and State vs. Theocracy - crosses to Liberty Bells or crosses to production - again, I don't see why you'd need the Liberty Bells. Production bonuses may be nifty (to get some more tools and horses, as mentioned). Even so, I think it's better to just arm the preachers and give them horses as well.
Wow, the constitution doesn't really matter at all! Maybe, if you could draft it e.g. at 25% Rebel Sentiment (and then declare independence later, at 50%), it might have a bigger effect - but as it stands now, it's a pretty useless feature.