gzt: This guy says he got the best outcome using a humidity sensor and a tiny heater. Humidity too high, the tiny heater turns on, causing the fridge to run and remove the humidity. Genius.

https://www.localfoodheroes.com/converting-a-fridge-for-drying/

I went down the rapid hole and talked to an expert diy home charcuterie guy, I'm not sure if it makes it clear but that heater method only works with a frost-free fridge, which I'm sure most people at home have, but the fridge use for my dry aging stuff, unbeknownst to me previously is a non frost free former drinks fridge. 

Long story short heater trick won't work for, and neither will any other method probably so I'll have to upgrade my drying fridge for best results.