Fred, the baffle is only for street and road riding.
The rocket nose cone things helped a lot. This showed me that a reflected wave was the source of most of my trouble. The cones reflected the waves to the muffler core sides rather than straight back to the exhaust valve. Now I tried something different. I drilled 1/2 inch holes in the baffle ends. This change also reduced the reflected wave and it lessened the back pressure, too. This modification helped a lot.
Next, I pulled out the carb slides and replaced them with a set of slides that I drilled. The air hole shown is drilled out from 2.5 mm to 3 mm using a #32 drill bit. This trick I learned from the Jenks Bolts carb tuning pamphlet mentioned in a previous post. The bike ran even better in the reversion zone.
The engine ran better, but it was not smooth in the 3,000 to 4,000 rpm zone, especially at 1/4 to 1/3 throttle. These Bonnevilles wear out their jet needles and needle jets and they run rich at lower throttle openings when this happens. My bike has 20,000 miles on it and it is overdue for a set of needles and jets. I had a set of new jets and I installed them. This made the bike run really well. The reversion problem is fixed.