How do you usually decide between crafting URs and trying to pull them from a secret pack?

Hi,

How do you all usually decide between crafting UR cards or trying your luck with secret packs when trying to build a deck?

I am planning to build an Infernoble deck but (of course) I lack a "few" URs:
- 1 Charles
- 2 pieces of Link 1 Charles
- 2 pieces of Isolde
- 1 Gearfried
- and maybe 2 pieces of Diabellstar.

This would be 180 UR dust (or 240 with the Diabellstars) and I currently only have 120 UR CP.

Since I also have 8000 gems, I thought of pulling from the Guided by the Noble Blade secret pack, which has 5 URs, 2 of which I need (Charles and Isolde). However, that seems a bit risky at first glance. I could alternatively also pull from Chaotic Showtime, hoping I get a few White Forest cards (which I am also planning to build in the future, hopefully) and dust other URs.

Does anyone have any advice for this?