The chain is 8mm and I prefered the idea of chain for the weight. I also liked the idea of it all being continous (the link would be welded and not shackled) instead of adding the extra chain on the occasions I would use it. I have often read comments from live-aboards that they would not use less than 100 mts.
We often anchor overnight in various places fishing, and sometimes it would be advantagous to anchor in deeper areas. We have also been caught out by weather changes overnight so we are looking for a bit more peace of mind.
Reducing the amount of water would be a good option for a longer passage.
Thanks for your comments.