Sure, I’m working on page 66 of The Planets here. You can get a copy of the score on IMSLP.
This page is currently very close to final layout and it mimics (for the most part..) the Dover Publications (Boosey & Hawkes 15970) engraving. In particular, look at bars 231 and 232 where you’ll find some key changes. There are quite a few things to unravel here, though.
The Piccolo’s, Flutes, and Oboes on bar 231 show A♭ (four flats). If you use your natural inclination to make those signature changes as independents, they will look alright in the Galley view, but on a condensed stave in Page view you’ll find the the key signature missing, although bar 231 will be indented as if there should be a key sign there.
Give it a whirl - remove all the signature changes on 231 and apply them only as independent changes and you will see what I mean.
The solution was to make a master change in key signature to A♭, and then set everything not intending a key change back to what it was, either atonal or in the case of the harps (which needed to be deliberately set correctly and were fortunately empty hidden staves.)
Now that mostly works, except in the narrow case where you need to do the same thing again in the very next bar. I.e, the condensed Bassoons change to A♭ in bar 232. Here again, we make the master key A♭ again, and then back the changes for everything else except for those instruments already in A♭ - you don’t make those atonal, you let them keep the new (but the same) key signature. i.e the strings in bar 232.
Lastly, for those restated key signatures, to make them disappear you have to set them a custom size of 1.
It’s a very roundabout way of getting to a final result, but I can’t help but wonder if someone else has had this issue and maybe had a better solution.
(FWIW, there are plenty of odd meters and metric modulation going on here, if you’ve never done it before this might be a rosetta stone for someone.)
Mercury.dorico (3.6 MB)
Probably too much self-doubt on my part… 
