Err on the side of equality. More important than the split is to have vesting with a cliff, because given the circumstances, some are likely to leave in the first year.
Given the circumstances, I wouldn't be surprised if some people leave within a week, never mind a year -- but this makes me wonder: Why is a vesting cliff necessary? Someone who leaves after 2 weeks hasn't made much of a contribution, but it seems entirely plausible (to me, at least) that they've made 1/26th of the contribution of someone who leaves after 1 year.
Or to put it another way: Every week you become a more valuable part of the team as you learn about your niche and solution and as you build a product and relationships.
