Walker decks is too thin to mulch well. Even with gator blades on it......mulches terribly.
I use two Exmark Lazer Z's 46 with triton decks. Both equipped with the factory lowering rim and installed mulch kits. OEM mulching blades. Love the results for bermuda, and zoysia grass.
I couldn't tell you anything about the SCAG since, this model isn't sold down here much. It is considered a knock off brand to our dealer's. There hasn't been much call for the mower in our peak Exmark market. Cubota, Walker,Exmark, and Grasshopper is all that is purchased in my area. We have learned how to use each mower to its best benefit.