warwickl said..
I am getting mixed views as some say 55cm mast others say 70cm.
I've been using 55cm so far.
So after comments from SB guys.

If there isn't a problem with dragging the foil around on the bottom, I think the longer one is better.

I had a 60 when I started which fitted the shallow reefs I tend to foil. I'm on nearly 85 now and I have to be a more tactical on small days but it takes drops way better and pumps better too.

Warwickl I am only a begginer ( coming up to 10 days) and switched last week from the 55 to 70cm mast and find it much better. 2 friends who I foil with are on 70cm masts and even though well ahead of me, recommended it. It looked a little intimidating at first but I rarely breach now and it is better in bigger waves. The only thing I notice is having to walk further out to stop the foil hitting sand or reef and the height of flight being higher but trying to learn to keep this lower.

It's great having the longer mast avoid some of the excusable breach beatings. The catch22 is small waves need shallow water, so if you're drafting almost a metre, you'll be in water too deep for comfortable learner waves. One way round that is finding a spot where the foamies roll into a channel so you can gut slide in.

The best mast length is one that doesn't bottom out in your foiling area.
Basically 55cm or 60cm in most beaches. Don't fly too high! Keep level. Better to touch down before going too high.