Alternatives to the Minimoog Model D Opto-Key upgrade?

[synthatron]

I have a Minimoog Model D from '74 with keys that are clanky and hard to play and struggles to keep to the right pitch. Half the keyboard makes these sweeping siren sounds rather than stable notes.

I was hoping to get the Opto-Key w MIDI retro fit from This Old Synth:

http://www.thisoldsynth.com/Optokey.html

However since Covid they've been unable to make any more of them and there is no sign of things changing any time soon.

I liked the Opto-Key because it seemed like it makes playing the Minimoog an absolute dream while also adding a MIDI input. Currently the keyboard is pretty much unable. I have had some success using the Kenton Pro-2000 to send it external gate and CV but this is also quite clunky and requires a lot of constant fine tuning because of how the Minimoog works. From my understanding they weren't really designed to be cleanly sequenced, rather the pitch CV input is more for something like a foot pedal or additional vibrato.

I know there are other MIDI retrofits I could easily install like the Kenton that would solve the problem of clean sequencing but I'm still wondering what alternatives there are to the Opto-Key as far as making the keyboard playable again? I've cleaned the J-wire as best as I can many times but I think between that and all the contact springs that each key has it is just too corroded to make playable as is.

Any ideas?