It was dry-ish when I did it last year, so no probs, but there are a couple of grassy sections that I think (from what riders were saying) can get bad with the mud if it’s wet. It’s certainly rocky so a lighter weight tyre might be vulnerable there. I’d perhaps take both and see what the weather is doing on the weekend.
Either way I’d just run whatever I felt was best on the stages and not care about drag on the link-ups. It is a big day’s ride but the connectors are just casual pedalling so it doesn’t really matter imho. I don’t know if cut-off times are even a thing anymore in enduros, but if they exist it’s just nominal to keep everyone moving around the course. There’s an alehouse on the ArdRock circuit, for example – don’t want any competitors bedding down there on raceday.