Thanks Roger for the reply.
I understand your point of view and for sure it is much easier with a smaller fin especially off the wind in stronger winds and you can sail it in shallower water.
If this is a common point of view are Starboard going to change the fin supplied with the board in the future.
For me I would love to try it with an even larger fin say the 75 cm in the very light winds but there is no hope here of getting one.
Your jibing technique will be different using a smaller fin as you say the fin is less likely to throw you in.
So if you have time can you please post it. As I will keep my advice ( if wanted ) to using the Serenity with stock 70 cm fin.
Hope you have a good summer.