Not really, but I think you could look up what a dingo, Kanga or similar produces, (I have not looked yet) and that would give you the spec I guess. I am thinking about 5 GPM but I may be way off.
Sounds like you have a drive, now make a bracket to hang it from your bucket and plumb it in with a diverter and you will be digging holes.
Already have a 3rd function for the grapple. 13gpm. I'd feel more comfortable if I knew the specs this thing was capable of. I am not sure what happens if 13 gpm are applied to something designed for 5 gpm. Maybe it just spins faster...maybe it make many little pieces of itself?
ac