Already Alban Berg et al. used the "new" beaming in the '30s! In UE Lulu score (acts 1-2) there is a picture from the manuscript score; it is beamed by the beats, as an instrumental line.

I think you have one "sextuplet 1/32" too many on the first beat (original post). Remove the dot and everything should go well.

The MOLA guideline of 8.5 mm staff is rather large, even for strings and percussion. I think the "industry standard" is 7.5 mm and can be even 7.0 mm, especially for winds.

All are right, Motet :-) mit Ausdruck is literally translated to "con espressione" if you want to be ûberprecise.

Could you perhaps use another time signature (hidden, even) for this passage? It could help the non-professional singers to have the triplet "on beat".