Just thought I would update this since completing the hike in September. Although I hiked a lot before going, I still found it very hard and tiring, especially when carrying around 13kg in a backpack. Technically it is no harder than Tryfan/Brystle Ridge, but there is nothing in the UK that quite prepares you for the terrain.
We would get up around 6am and be on our way by 7am to avoid the sun on the initial climbs.
The huts are very basic with ok ish food. We camped each night and only had a storm on one evening, when camping at around 1900m.
We also did the detour up Monte Cinto on day 4 which included a lot of scrambling.
(I’ll upload photos later, when I have worked out how to do it!)