When I watched you shoot sporting clays with those subsonic Winchesters, James, I definitely noticed lower noise. There was also an appreciable difference in time following the longer shots that your birds would break compared to those of us that were shooting zippier loads.
You were wise to load up on Kent when you did I think. Likewise with your stock of nontoxic cartridges.
For 90% of my shooting in 12 ga. I'm loading my own 1 oz at 1100 fps for clays and upland. Same load whether the (high barrel condition) gun is proofed for nitro or not. Some of them I cut down for short chambers but most of my guns that have nominal 2 1/2" chambers can still be used with folded-crimp plastic hulls that are nominally 2 3/4". I buy the odd flat or two of 1 1/8 oz target shells to shoot through more modern guns (and also to restock my supply of hulls for reloading from time to time)