A lot has already been said concerning compensation - in this thread and in Matt's thread a few weeks ago - some of which is a bit controversial. From my experience I think there are several factors to consider.
A few years ago I picked up a Mahalo Les Paul, just on a whim, brought it home, started playing away and suddenly realized that the intonation was way off - really bad up and down the fretboard. Anyway, it had a compensated saddle (where the C and E strings are slanted back slightly). By comparison, our Bruekos have straight saddles but the intonation is really spot on all the way. So much for compensated saddles. I know that some makers use them, but they don’t necessarily guarantee good intonation. With the Mahalo, it may be that the rest of the instrument is not set up or “dressed” properly. We’ve never gotten around to pulling it apart and fixing whatever is out of line – there are just too many other, better instruments around our home that we would rather pick up and play.
The Bruekos do have minimal compensation of the saddle position, as do all the ukes we’ve made ourselves. By this I mean that the distance from the twelfth fret to the saddle crest is slightly more than the distance from the nut to the twelfth. So, for example, on a soprano uke with a scale length of 340 mm your saddle might be about 342 mm from the nut (but the twelfth is still at 170 mm).
What else makes a difference? The type of strings, string gauges, tuning, tension, action, neck angle, fretboard height, saddle height, and so on.
If individual compensation per string makes sense at all, then only when you determine that the intonation on the fretted C and E strings is sharp even though the G and A strings are exactly right. But that's really fine tuning
HTH,
Erich
