I actually think the slighlty lower ROF of the M-4 37mm might not be too bad, the NS-37 burps them out a bit too quick for only 30 rnds of ammo.
In any case, to hit with the spud thrower, you get in close anyways. I guess we will see. Its interesting to note that the N-37 on the MiG-15 also had a slower velocity, 690 m/s. I saw an interview with a Chinese MiG-15 pilot that said you needed to get closer than 200 yards, which sounds about right to me.
Go for the kill with the 50s, and if the 37mm hits, great, if not, oh well.