Key arm for spine.
I think I understand your question/curiosity. Either key can be altered in several different directions. For example, if you bend either key upward it has a natural way it will want to bend (e.g. in a sort of clockhand arc, rather than just being "raised," if the goal was to bring the key higher vertically from the body, and in a way closer to the raised hand). If you change that (the vertical orientation), then you probably have to make a second bend to the plane of the keytouch relative to the arm it's mounted on, or equally relative to the (curved) surface of the body. For me, if I was doing that I'd probably bend vertically with fingers and then change the plane with plastic jawed pliers, and the entire time I would be concerned about accidentally offsetting the screw/roller/screw-threads relationship. There would be two hazards re the roller: causing it to bind and damaging the screw's ability to be removed (if already in. Breaking the roller would be somewhat lesser danger for me. I don't think any non-tech or new tech should play around with that on an important horn. I'm not tooting my own horn but the reason that I'm not too nervous or hesitant to do this kind of thing is largely the full replacements and "modernizations" -- things like this are in play on every single key.
The more you change the vertical position of the keytouch relative to the hand, the more likely it'll be that changing the plane of the keytouch surface will be necessary. This is kind of particularly a concern with low Eb and C because the finger sometimes goes straight downward and other times slides.
For bigger changes I might think about risers, probably marine epoxy, but I haven't done any of those in quite a while.
As far as tools and techs, eventually I think a lot of these choices become sort of rote and unconscious. It must be that way for you, with saxophones, too. I rarely think much about what tool I need to use. Habit mostly determines it. But I do think about fingers vs pliers vs tapping with a hammer of some kind, still. Sometimes I kind of force myself to because sometimes instinct is to be lazy and just use fingers (where a small hammer might be wiser, because a hammer would involve finding the right one, reaching for it, etc., and the fingers...are already on your hand lol). Small changes are definitely less likely to be overshot with the right hammer.
Surfboard making is a good alternate/similar example: at any time while working on a surfboard blank I have an option of 4 or 5 different tools, several different grades of abrasive action with each tool. I've only made 80-something boards, but it's already pretty mechanical, which tool instinct/habit will tell me to grab, and not a lot of thought goes into it.
It's neato to watch someone else work. That's a tradition in surfboard making. Part of ordering a board (in normal times) is that you get to watch the "shaper" (board maker) work. That is how I learned to make surfboards, some lessons from a friend and then paying guys to make boards so I could watch them work. I love watching masters work. There's no lost motion, they're like machines. I think watching a factory worker would be like that, because production is where technique becomes efficient and mechanical in that way.
For some reason working on saxophones is less like that, at least for me. Something to think about for me, personally, why that is, because I've got a much better mastery of working on saxophones, but I don't see myself working on saxes ever looking like what I might look like working on boards 100 more boards from now. Weird and interesting. Probably someone that worked production lines, assembling saxophones, would look more like that when working (efficient, no lost motion, a machine).