[Riklin]

I think it uniformly works based on a ratio of 4 skill points equaling 1 hitpoint, per bandage/bind wound attempt, with a minimum of 1 hitpoint healed. That is supported by people saying they can bind up to around 86 hp per bandage. For all lvl 50 characters, with bind wound skill maxed (max skill at 50 is 275) would heal for 68 points (depending on rounding).