Note that some of the sealants they recommend are actually sealant adhesives. I used the 3M 5200.
The tool they provide for holding the through-hull to prevent it turning is useful if single-handed (well two hands but one person!) but if there are two of you it can be easier to insert something else into the outside to hold it in place. That way you don’t need two hands, two arms, spanner etc. all working within a small cupboard.
The membership association for owners of Dufour Yachts