Well, my 2d is more or less repeating what's been said already, but oh well. In brief: 1 > 0.
I prefer to use my domed tinies as SYs; with some BSYs and orbital cargo bases, these planets can pack quite a punch. If you've got decent storage, you can also mothball ships as they come off the line and save them for a rainy day.
About the only exception to the SY rule is if the planet happens to be on a path between WPs. Then, I build a resupply depot, which saves some of the micromanagement. Not that I mind micromanagement; I just like to choose what to spend my time on.
If I run across a tiny with >130% in one resource, I usually put the appropriate extraction fac on it.
The training fac idea with two moons is a nice one; I'll have to put it into use in some PBW games here pretty quick.

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The Unpronounceable Krsqk
"Well, sir, at the moment my left processor doesn't know what my right is doing." -
Freefall