Where's the next weak link in my analog chain?

"I was strongly considering selling the 20/20 to get a Chinook SE while they are on clearance."

Your table/SS phonostage is solid.

A tube phonostage could be a more profound change than what been suggested.

Naturally, YMMV.

None of those wiring items will objectively change the sound so the obvious choice is the cartridge.

+1 for a better MC

Why?  Cartridges ware out eventually. You are already committed to buying one or retipping the one you currently have, so start there!

FYI - I am very happy with my Hanna ML, which is on your short-list (my system is posted).

Good luck with your decision.

Bang for buck? The new Hana SL MkII. For $850 it is hands down the best under $1000 cart on the market, and maybe even $2000. It carries a lot of features of their higher end Umami carts and leaves enough money in your wallet for cables, if you are so inclined. The move from even a great MM cart to a MC has always been a major improvement in my systems, starting with an upgrade from an Ortofon VMS20  to an MC-20 almost 50 years ago. Fast forward, and the Hanas shocked a lot of people, providing the SQ of multi-kilobuck MCs for a fraction of the price. 

I went from a Goldring 1042 MM cartridge paired with a Sutherland KC Vibe to a Hana ML moving coil cartridge and Sutherland TZ Vibe.  Huge difference.  Some of the improvement is likely from the phono stage upgrade.

The Goldring 1042 is a nice cartridge for the money. Perhaps comparable to what you have now.