Wade,
As well as I’m sure you build your slides, you can probably lap in the upper ones with lava soap suds mixed with lamp oil until those slides float very nicely dry, and then use lamp oil on them - to lubricate them - once they’re clean.
The lava soap suds + lamp oil lapping compound will take about 2 to 3 times as long to lap satisfactorily with your preferred nickel silver tubes - compared to brass, but - with patience - will do very nicely… or perhaps you’ve already lapped them in, using some other compound.
The lower ones (which tend to just sit), you could sort of half-heartedly lap them in with the same materials, and just put a little lamp oil on them every few days to make sure they don’t seize…
Alternately, the lower slides could accept a nearly nonexistently-thin thickness of STP oil treatment, which you could keep from drying up completely (virtually forever) with a splash of lamp oil, now and then.
I don’t enjoy maintaining my instruments. I don’t enjoy cleaning my instruments. I do enough of that with other people’s instruments. I just want to be able to pick them up and play them. The tack outlined above almost completely defines that my instruments stay clean and stay lubricated. As you know, this is both very easy and very cheap.