The answer is always “enough as is needed.”
Anyway, consulting this chart here, assuming solo for them both:
If you wanted a 50% chance of NP1 or better for an SR: 167 SQ gives you a 56.45% chance.
If 90%: 500 gives a 91.86% chance.
For a coin flip’s chance of both, I’d suggest ~334 between the two. For an ~80% chance, I’d suggest ~668.
The literal only guarantees in this game are:
- The SR gold card per 10x (later 11x come 4th Anni).
- The Guaranteed non-Limited/Locked SSR we will get in 2ish years with the 20M DL campaign.
- The Guaranteed SR campaigns for non-Limited/Locked SRs (and even one of them is up in the air, specifically the Babylonia-related one next year due to us getting it way early alongside Merlin’s animation update, etc).
Otherwise the only amount that is required and can be guaranteed to get you what you want to snag, is as much as it takes to snag what you want.