Best place to roll white night?

[djumbreon]

my codex is 98% complete. as far as I know, he's all I still need. I've only rolled him once, when I was opening the safety department but opted out in order to focus on farming alphen gear in tipereth. Haven't rolled him again since and feeling disheartened.
Is there a specific spot or day you can run a high chance of rolling him? like how days 21 and 23 easily net you guys like melting love, silent orchestra, or nothing there?

[Grim Xzag]

There is no specific day
https://docs.google.com/spreadsheets/d/1ZCfaw51PIZk93opHr8hkLNVxPvHHU8_xyq7IRV0R2uk/edit#gid=0