getting close to the payoff now... final challenge, retain the nut in the arrestor housing.
pilot hole in housing (first attempt on left was too "high" to catch the meat of the nut):
marked and drilled the nut:
found a roll of fiberglass house insulation, peeled off a bit, wrapped the perf tube tightly, eased/packed it into the arrestor housing, threw in a self-tapping screw and went for a spin!
definitely less restrictive than the arrestor. had to richen up a bit, picked up 2-3 mph on the flats, but more noticeable in the midrange. all well and good, but the best part is IT'S QUIETER. that makes me happy since i'm free to open up the muffler chamber restrictions a bit more.