Artist's resources:
https://www.pixiv.net/en/users/1769484
Recommended samplers:
DPM++ 2S a - 18 steps
DPM++ SDE - 18 steps
DDPM - ~28-36 steps (Recommended)
Euler A - ~28-36 steps
Recommended upscale settings - here.
Recommended checkpoints:
V-Pred version is here. Check it out as well.