My last FoS character was an arial and it seemed to work best at night in one of the cities. When I would run my buns off into the sewers or the underdark it didn't seem to make a whole lot of difference no matter the time of day, both in the amount it fired or the number of retaliation strikes (which were usually only one and very, very rarely two.)

Helpfile makes is sound dreamy, but its probably not a legacy I would choose again in the future. Mostly due to the fact that when it fires it doesn't fire "well." If it did I would use it even if it was very infrequent that the legacy fires off.