hey man i seen a thread on here before saying that the crosman air pistol holster at wally was a perfect fit for the c9. Now they may not have been refering to the shoulder rig that your looking at but being that it is the same brand i would imagine that it is the same holster just with rig added. so i would have to bet that i think it would work for you im almost tempet to go check it out myself.
Capt. I use the crossman holsters for my c9, and cf380. Yes the 10 round mags fit perfectly. As soon as I get pictures I'm going to post how to's on converting to thumb break for the crossman ( no more buckles )and a really comfortable belt for $4.00 that will hold about 6 mags securley...............woody