Fortunately, I have a load of test switches on the way. Hopefully I can find something that works out of the box, or at least too much hassle. Including the Skies, but I haven't figured what 'work' needs to be done with them.
I'll try to let you know when I find out through my own experience, but I have read about the work to be done with Skies.
In stock form, Skies are not up to the standards of custom builders here. They are scratchy, don't sound great, and the springs are noisy. Further, if using the older 2.2 non-silenced Skies, they wobble heavily unless you use the 'no-slot' tops.
But with work they become noticeably better. First, they need substantial lubing. The stem contact surfaces for sure, and some even lube the tactile legs. The springs are the component of the switch that can legitimately be called bad. You should swap them, although the stock spring can be improved via donut dipping.
Once properly-lubed and spring-swapped, you have a switch that sounds decent and has a pretty noticeably tactility and coherent 'bump,' especially at lower weights. The Sky stem is genuinely good, and runs well at 62 gr up to higher weights. It runs better at 62 gr than Clears will. So it's good for making snappy light Clears.
[The bottom-out can feel like rubber-dome or mushy to some, so that's something to take into consideration. As well as the need to always use the tight-tops, which I think come stock in the Silent Sky.]
The U.S. distributor envisions OUTEMU Sky as a modular system consisting of housing base, housing top [no-slot being the preferred choice] different stems [Sky/Silent Sky/U4], and the spring. So you're best off thinking of it as a modular system. This is less trouble than it sounds, because you can order this in pieces, to make assembling custom switches easier than with Cherry MX.
And that is the 'work' you do with Skies. It's really about choosing and assembling the components.
The Sky stems are said to work well in TTC Gold Brown V2 housings, of all things, which I intend to test. There are also "Sky Pandas."
EDIT: Some people lube the Skies lightly on the sliders with Tribosys, so it's a matter of preference.