Wow that's lovely and I can imagine how good it is.
I have a Shuker neck on a P bass partscaster that he also assembled and set up. Absolutely sublime instrument.
Personally I'd keep the Jazz. It sounds like you're just bored.
T-birds are cool, but have terrible ergonomics and are less versatile.
The other two are Jazz adjacent.
I'd definitely recommend speaking to Jon. Like I said it worked out basically the same price as a similarly spec'd Warmoth guitar neck. The only downside really was the wait.
I've just finished a build with all gotoh hardware including elephant ear resolites. Really impressed with them. They're stable, feel great and obviously are ridiculously light.
Here's a photo of them in situ.
Fair enough, assuming it's the same result through both that's my hypothesis disproven.
Could it be a dodgy string or pickup?
*edit* or something set up related?