Arkman,
Hope the fly was barbless, but since it took 45 minutes, I suspect not.
As for line speed, there are way too many variables to just come up with a fixed speed. The action of the rod is a big factor, the weight of the line, the weight of the fly, the amount of wind you are fighting, the distance you need to cast, regular cast or single haul or double haul.............so many factors.
However, it would be interesting to know the range of speed a fly or fly line can have based upon all those variables.
Naw, sounds like a lot of work, just go fishing instead. :)
Larry ---sagefisher---