Sorry, I thought my first message hadn't got through so I wrote another message!
Amplitude levels shouldn't cause a crash. Are you filtering your GEN10 tables with a moogladder? Try taking the moogladder out and see if it helps. Does it actually kill Unity or does it just causes it to go unresponsive? Perhaps you can monitor your system resources too and see if they are being pushed to the limit.
1550 instances of an instrument does seem like you may be pushing Csound to the absolute limit. I'm not sure which approach you took in the end, but are you turning off each instance when it's done? Or is it going off on its own?