Forgot to mention the pogo pin. The closest match I was able to find is this one:?https://www.aliexpress.com/item/4001294383416.html?spm=a2g0o.cart.0.0.fd0238danIFNlV&mp=1 . (M1648 version, 3.0x18.5 5Amps) But there zillions of pogo pins on Aliexpress and from distributors, so there might be better options available.
I consider to 3D print nose cones as well, but haven't decided on the material yet. Which material would have the best properties in terms of surface and bulk resistance and moist absorption, if those matter at all for the given dimensions? Anyone having any experience? And what should be the maximum gap between tube and cone? I guess a wide gap will cause FR anominalies.
Jan
