The bigger blower should flow more air with less restriction through the blower equaling more air ingested by the engine with less heat per revolution than the smaller blower. So when you turn up the boost on the larger blower you get a proportionately bigger intake charge at a cooler temperatures per psi and make more power with less boost.
It can become a choke point at a certain point depending on the engine. In your case you should do the math on the swept volume of each cylinder, then take the output volume of the SC multiply by the desired rpm operating ranoutge.
With that you can figure figure out how much air you need going into the engine at a given rpm and compare it to the output of the supercharger at a given rpm.
Just remember your SC is turning faster than the crankshaft so you'll have to figure out the ratio of the rotor pack to the crankshaft. IIRC M122 max rpm is somewhere around 18k RPM. Obviously the heat output increases from the supercharger the faster you spin it.