I've been trawling the internet in search of information on the YS-11 in order to make more meaningful and helpful bug reports that will hopefully propel this add-on towards a greater level of completeness and accuracy. I've turned up very little, so far, but I found this interesting anecdote regarding performance on PPRuNe from an ex-Piedmont YS-11 pilot that aligns with some feedback I've seen here and on the MSFS forums regarding performance, particularly after takeoff:
I hope this is useful to the devs.