Hmm, interesting.
So the fact that the ID is so high is because I caught and sold a bunch of slaves in between finding ones I liked.
Does the unique ID stay with sold slaves (until they presumably vanish from the market), or are they given a new ID when you buy them back? I've been using a sell-and-buyback strategy to get Mansion Upgrade points and a brand.
If selling slaves gets them out of the pool but maintains a higher slave counter, would it be possible to change my preferred slaves to the IDs e.g. 12, 13, 14, 15? I could either ignore the relations/interactions data, or figure out how to swap a few numbers around.
I wouldn't be messing with the unique/quest slaves, yeah. I pretty much always use the same starting slave specs anyway (I found a nice setup that works with my overall story concept, and gives me a neat pun, so it'll be a while before I tire of that specific character).