I’ve never run skins, but I think each course might handle that differently. That is why above I have the organizer provides the rules step. For example, I have played where 2 birdies on the same hole split the skin where most play that 2 birdies on the same hole cancel the skin. I think most have played where no skins on day 1 carries over to day 2, 3, etc. I am sure there are tie breakers out there, just not sure what they are. Maybe the veterans can chime in here, but I could see things like most birdies (all week or by day); lowest score for the last nine, last 18, etc. as possible tie breakers. What I am sure of is that the past organizers have had ways for resolving ties.