I’ve been experimenting with various combinations of my VST libraries and NPPE 5 an thought I’d try percussion. I used BBC SO, Synchron PRIME, Iconica, and Spitfire SSO 2024 (it has Tempe Blocks and crotales). I used NP 5 reverb. It used 0.6GB of memory. I’ve found that even when using NPPE 4, I had to experiment and try various combinations of VSTs and templates; that’s why I’m so pleased with the options Dorico allows for. Sometimes, the best ‘sound’ is Dorico’s HSO, sometimes it’s NP by itself, or sometimes a combination. It could just be me, but I also think that the instrumentation, dynamics, articulations, key and range of a particular work may affect how any particular VST library may affect playback-with or without NotePerformer. That’s why I love the flexibility with Dorico-we can experiment (although I dream of the day when we can simply apply a template and have the LSO come out of our computers.) 
Percussions is a family of instruments where third party libraries (Toontrack, Spitfire, VSL…) offer gorgeous solutions. And probably one where I don’t feel the need to use NotePerformer (with or without NPPE), since percussion maps and expression maps fill my needs, and the raw quality of the samples is outstanding in those libraries, at least to my ears.
If you want me to export you the same piece with different libraries, I’d be happy to do so.
Marc,
What a generous and response! I have put the Dorico file here. I know little of how to alter, let alone create percussion/expression maps. I would be very grateful for your experienced help and advice. We all want our music to sound as good as possible. Thank you SO much!
Gary
Precociously Persistent Play for Percussion 9x12.dorico (2.1 MB)