Strength of the hitch to frame is the shear strength of the supplied bolts. If there is no way to get another nut into the frame (think a wire wrapped around a nut), then the most reasonable next step would be to weld the hitch to frame.
I'm in Cartersville, would be glad to look at it. Shop is rather full right now with 3 other jobs but if you want to stay in touch I might be able to get it in middle of next week.
Try Hardy Ford in Dallas. Gave me the best deal I could find in NW Georgia.
I'm retired, I've got a lot of time to research these places.
Best car deal I ever did was with Woody Folsom in Baxley, all over the phone, they delivered.
Had this same thing happen to me with Champion plug in my Jeep about six months ago. Kept getting ignition coil fault on my scanner. Replaced the ignition coil, same result.
Pulled the plug and had the same thing that you posted a photo of.
NGK now.
At the point of your arrow, you can cut around the "domed" portion of the existing cable and remove the 90 from the original "cap". Retain the rubber boot from the original cable and feed the cable through the new cap. Be certain that you have enough "take up" at the adjustment on the thumb...
Might give some thought about using a reputable independent V-Twin service provider. I don't think I would take it back to a location that possibly screwed me over in the first place.....