It is just less than half an equivalent BG (35+ 12K feet -> 60 equivalent miles ) plays (65+ 27K -> 120 equivalent miles). For the most part it is good going under foot too, IMHO on average better and more runnable ground than a BG. So BG pace is maybe 11-12 hours.
There are just 12 hours of daylight at present, dropping to 9.5 by the end of october, so still doable for a couple of weeks at BG pace, perhaps finishing in gloom. The discussion makes me tempted to do it again.
Sunrise start is 6.15 at the mo , moving to 7.15 over the next month.
The only thing non obvious is advisable to "know" beforehand is the route to the first two tops, after that the rest of the route is on various race routes and paths. Nice route