Making Harmony with a Blade bow does have its advantages...
-10 WSM to easily attain strafe/normal attack breakpoints.
low str req, more points can be put into dex
non-zon specific so can be used by other characters
Another non-zon specific choice would be diamond bow with it's not-so-high str req and the nice tight damage range. But at 0 WSM, reaching the next strafe breakpoint would require more equipment sacrifices...
Depends more on your playing style I guess... If you want speed, Blade or Mat. If you want damage, GMB would be your chocie...