Standard settings and model sampler are used for ZIT.

There are no specific settings for illustrious, use your own settings.
The default settings will work just fine:
resolution: 896x1152
sampler: euler a
steps: 30
cfg: 5.5
hires. fix: latent (nearest-exact) x1.6

Krea 2:
Checkpoint: krea2_turbo_int8_convrot
Cfg: 1
Steps: 8