In case anyone else ever finds themselves in the same pickle as I did, I went with some Van Damme 268-100-000 cable plus TA5FSH and TA3FSH connectors from Switchcraft. Works a treat!
I did two things to my MX-VYNL to make it perform the way it does now.
The first was to add a linear power supply. I got mine from Swagman (search online) and is one of three that I have from that company. I also removed and replaced the janky power input coaxial plug on the MX-VYNL with a more robust plug with a locking collar (GX16-2). If you have basic skills you can make this modification easily, dropping the power directly onto the rails on the circuit board and removing some cheap and quite nasty coaxial plugs which are notorious for a weak connection.
Second, I made an interconnect for my SMEV tonearm using a Cardas S DIN E plug to a Neutrik Rean Mini-XLR RT4FC-B four pole plugs with Mogami W2534 cable to which I added extra shielding. This was pretty cheap to make, just took some time and patience. I made the cable as short as possible. Then I made some balanced output interconnects using the same Mogami W2534 and Neutrik NC3FXX-B plugs to hook up the MX-VYNL to my Pre-Amp.
The combined result was such a vast inprovement in performance. Not one of those "yeah, I might be able to hear a difference" exercises in confirmation bias, but a significant, objective decrease in background signal noise and overall increase of sound stage. All for very little money.
Conclusion:
To not use this little beauty in balanced mode is akin to running a Ferrari on kerosene.
To not use a decent linear power supply is to accept the cruddy fundamental power you get from a $2 wall-wart.