Optimal input level for highest accuracy when using NDSP plugins?

I’ve been posting online a bit recently about this subject, and it would be amazing to have some concrete numbers on what internal reference level the Neural DSP plugins are designed to work at.

I believe that the Quad Cortex DI input is 9.5dBu - if someone was to use this as a DI input for the Neural plugins, and with the plugin input at 0, is this the most 1:1 level for using them?

I’m not looking for responses like “adjust until it sounds good” or guessing - there will be a fixed value used to model/capture the amplifiers that gives the most accurate response (as in the same as plugging directly into the amp).

I believe it to be somewhere in the 9.5dBu-12dBu range but anything more concrete would be greatly appreciated!