Recommended exciter is:
Dayton Audio DAEX32EP-4 Thruster
32mm Exciter Speaker 40W 4 Ohm
This cable looks decent but shop around on ebay or other musical equipment stores.
I did get some progress with the isolators, looked at several springs and different compounds of isolators. Its not been easy finding a good match in fit/stiffness.
Here are two options, a new spring combo compared to a sandwiched isolator. Other vibration/sound-deadening materials will be added with whatever options works out best.
It's getting a good combination that fits well and also can work better than a standard or single solution.
To mount these better would need a wider profile
Something like 80mm drilled in the center.
Still some options I want to look at but my focus is on my own build at present.
Sounds good on the preferred exciters, those are the same ones I linked, so I'm on the right track. Regarding your recommendation to search eBay for the Dual Male XLR to 3.5mm cable, I had posted the below which seemed to be the right one? I know absolutely nothing about audio though, so I will wait to order until it's confirmed to be the right one.
Experience a solid connection and clean signal transfer, by virtue of these cables' no-compromise design. Ultra high density spiral shielding wards off RF interference, while a conductive PVC sub shield defends against electrostatic and handling noise.
The new isolators look great, and glad to hear you're focusing on your own rig build. Looking forward to continuing to follow along with your progress!