So far, no one took salary. Everyone would start having similar salaries at the same time
I would say: 57 37 5 1 potentially seems appropriate to me.
A and B having real money at risk get the lion's share and everyone gets some credit proportional to the time they have volunteered to get the thing going.
While it is all still on paper, you might also want to work out who's pot future stock incentives come out of. Is it A only or A and B equally or proportionately? Alternatively, do you carve out a block now for such purposes perhaps based on all 4 contributing proportionately to the block.