I notice some interesting enharmonic spelling choices. E.g. Bar 32, you've got a Bb minor triad between the celli and violas, spelled with a C# instead of a Db.
Then in some places you have lots of flats, and I think you're changing mode here, rather than moving to a different diatonic key? Wondered if it was difficult to choose which spelling to use?
Sometimes when my music gets very chromatic, I find I need different spelling in the transposing instruments, which is an added complication! Seems to apply especially to Bb instruments, like clarinet and trumpet.