I did this last year.. over 3 days, although the last day was only about 5 hours.. could of squeezed it into 2, but that would of been a fair amount of effort, and I'm lazy
I wouldn't contemplate doing it clockwise.. The heather is very very deep heading up from the dam, and would be a complete nightmare to go uphill in.. It was a nightmare downhill ffs!
As for water.. The northern 4 arent so big that you cant carry enough to get over them.. On the affrick side, you follow a burn all the way up to the ridge, then there isnt more until Carn Eighe bypass path, and you will also get some from a wee stream that comes east off the ridge, just before the final ascent of finlay.. Nice camping there too if it isnt too windy..
Would definately be up for doing it again.. Dont know if I would be free when you are going though.. but keep Leithy or me informed and maybe we could fit it in