I would leave that valve where it is. It's perfect for a roto-tiller. Roto-tillers have large speed reduction and relatively low spinning diameter (radius of gyration); so, they have very little inertia. The blower fan, however has a large inertia. I would suggest you use the snow blower motor in single rotation, with the return line continuing to the rest of the system. This means you can't reverse the blower, but will protect from blowing out your shaft seal or cracking your hydraulic motor like I've seen happen to Hydro-Vacs. I suggest you use this flow-control valve to manually ramp up speed ~1sec and ramp down speed ~5sec. You use a second similar valve to control maximum travel speed. You should also add a relief valve to limit system pressure.
Even cheap valves add up, eh!