Hmm OK thanks, interesting. I have recently been on a big brass kick. I got two Squape Rs clones, one Ivogo and one SXK. Both have stainless positive pins, which are M3 screws. The Ivogo pin was a bit too short, and I had wildly fluctuating TC resistance. So I bought some M3 x 16mm replacement screws, in both stainless and brass.
I then measured their resistance with my Chinese 4-wire 'micro' ohm reader, and was surprised at what I found. The resistance along the stainless M3 x 16mm was around 0.0025Ω. On the brass, it was 0.0002Ω. 12.5 times lower than the stainless.
So I then swapped out the SXK positive as well, and tested the real life benefit on my SX Mini M. A Titanium build that measured 0.421Ω with the stainless screw measured 0.418Ω with the brass - a 0.003Ω difference.
Now I am the first to admit that 0.003Ω is not a huge difference. It's not even 5°C of TC inaccuracy. But I'm of the view that every little helps, and it all adds up - if I can cut out as many little 0.003Ω's and similar in the atomizer, I will get the most accurate TC. And I further admit that part of this is just for the goal of having the most accurate TC, rather than it necessarily being a noticeable difference in the vape

Though there are places where one can cut out 0.01 or even more of inaccuracy, and those are more noticeable differences. And if in a single atomizer I could replace three 0.0025Ω stainless components with 0.0002Ω brass ones, then that could ultimately show a 0.01Ω of difference on the mod, and there we can be talking 10°C of improved accuracy.
(Interestingly the amount of inaccuracy from static resistance depends only on the base resistance of the coil, not the coil wire used - the higher the resistance of the coil, the less SR affects the accuracy. This is (yet another) reason why Titanium, Stainless Steel and Resistherm/NiFe30 are better than NI200 with its stupid low resistance. 0.01Ω of SR on a 0.10Ω Ni200 coil is 20°C inaccuracy, compared to 5°C inaccuracy with a 0.50Ω coil of Ti, SS or NiFe30.)
But in all that I didn't realise there could be an oxide risk. Although I do have a number of atomizers which already have brass parts, in particular my Aqua V2 clones and SE authentics which use an all brass positive path which touches the underside of the positive wire - it forms the 'floor' of the positive post, like I am trying to achieve with the Ubertoot. I haven't noticed any corrosion on those after a few months of use.
I will definitely keep an eye out for it, thanks. I dismantle and clean my atomizers regularly so if I see any discolouration I will stop using them in those places. I guess internal positive pins/paths will always be fine as long as they don't touch the coil itself.