I am using as below and it fits great

90 Degree 3.5mm 3/4 Pole Male TRS to TRRS 3.5/2.5mm 3/4 Pole Male/Female Headphone Stereo Audio AUX Spring Coiled Spiral Cable https://a.aliexpress.com/_ExZnWb7

I am using MCC from Moergo Glove80 with convex 1u in thumb cluster - should work for double press of adjacent keys and steno mode. Besides, POM is pleasant material. https://www.moergo.com/collections/moergo-keycap-collection

no one wants to come back, as well as mastering the optimal layout, e.g. ColemakDH… Unless you have to - it depends on your practiced skills and muscle memory. I once heard a good comparison that it’s like driving two different cars - a good driver can switch cars and drive each one without any problems.

Hi, I am using Fellowes Crystal 9112301 - generally good and comfortable. Common and easy to buy everywhere, but it is worth checking the prices, because there are differences between suppliers.