Any good quality fork oil will be fine, Maxima, Silkolene, etc... I run Mobil 1 synthetic ATF in mine, on Jer's recommendation. I have to say I am very happy with it, and it is cheaper than most fork oils. It is apparently around 7.5wt.
I have experimented with different weight oils in the past and in modern forks, I haven't found a great deal of difference actually. With the ATF, I can say, the clicker have a much broader effective range...that is to say each click has a greater impact. If you try it, you should likely start out about 2 clicks softer than original.