Your engraving looks good to me - the only change I'd make is measures 7 and 8, changing the C# to a Db. Basically, that harmony there is V - i (G major to C mi

Your engraving looks good to me - the only change I'd make is measures 7 and 8, changing the C# to a Db. Basically, that harmony there is V - i (G major to C minor, a.k.a. perfect cadence), but with a tritone substitution of the V. So what would normally be the bass is replaced by a note a tritone away. Normal bass = G, so a tritone away would be C#/Db, i.e. I# or IIb. But I# -> i is not a resolution whereas IIb -> i is. This is because, generally speaking, you can't resolve a note to another note if they have the same note name. So C# -> C doesn't resolve, but Db -> C does. Similarly, regarding the F#/Gb question in the vibraphone part, F# is better than Gb because you are resolving UP to G, so you want to use a different note name. The only questionable part is measures 11-12...I won't go into detail but I would say it can go either F# or Gb - both are perfectly fine ("depends on the person" kind of thing!) The rule "you want to use sharps when you're going up and flats when you're going down" is maybe only really true for chromatic scales, and even then it's tenuous. In general, you pick accidentals based on the key or harmony that you're in. Unfortunately music theory commentary does not translate well into English at all, so apologies if this comes across as gobbledygook. And make no mistake, I don't think in these terms when playing/composing music. It's more like a deep intuition you get after a while. EDIT: vcxy beat me to it!