Micanopy- I always enjoy a novel, "outside-the-box" conveyance of tales...hmmm I wonder Why?. It looks as though the evolution of your day was BucksDucksChucks. So sorry to learn that your wife's tent-emergence opinion query wasn't "Honey, would you mind if I bought this"? I am relieved however, to learn that SHE didn't show YOU how easy it was to Do the DING!! I think that my FWC encounter response, at some point, could easily have been "The last FWC officer revealed a hiding spot he never thought was possible = Under the engine Cowling!! Yeppir, he said he found a creatively-packed eleven FAT teal nestled there! I'm positive that YOUR engine and HIS future field-checks would guarantee a sniping, camera-ready You-Tuber Wheelbarrow-fulls of $$$ Always have enjoyed your creative side...your creative-writing skill is ICING!!
With regard to DIY slide-on bb swivel/underspin...I found that because of the limber nature of small, bb swivels, the blade's freespin can be interfered with by hitting the plastic or chenille body. Aside from your infallible, molded-in wire(insuring separation from body), another way is to glue/epoxy(your choice) a tiny, self-bent wire with two looped-ends then adding your swivel of choice
(note: a small beetle-spin harness w/blade is perfect) with only ONE quick snip.

u2s Congrats on your string of Medieval Fair attendance/cope...maybe next year I'll see you there to unveil the secret bell-ringing "sweet spot". It's more than what you've already described...you see, the hammer impact-point that 99.9% of contestants strike is mainly "dead-center"! The "sweet-spot" is actually the OUTSIDE edge! It's easily understood when you picture the fulcrum/leverage axiom. To over-exemplify = What if you impacted the INSIDE edge =little or NOTHING!

u2s