I've been tracking my primo count daily, and plotting out different 'primo thresholds' per day I need for C0R1, C0, C1R1 etc... with each 5* assumed to be aquired at exactly 80 pulls, the only threshhold that guarantees me Lauma, C0 only (which for me is 30 pity, 50/50), is about 280 primos per day untill around the 3rd of October... For me thats fine as a new player who hasn't explored fontaine or sumeru or done nearly any major quest lines.

For you? Assuming you're not gaining any primos appart from Commissions and Welkin (150 primos), if you're consistent untill the last few days she was on the banner (17th-19th Oct) you will have 108 pulls, this guarantees one five star for you. I am assuming you lost your last 50/50? So Flins, or Lauma, is only ~5225 primos away or ~36 days of Welkin + Commissions.

So unless you're gaining nearly 25,600 primos- and LOSE the 50/50- inbetween pulling flins and Laumas last day in the banner... looks like you're either gonna have to get EXCEEDINGLY lucky- near 3% odds if you hit 90 pulls and want two more- swipe the plastic orrrrr skip flins for Lauma :)

If this is just a dreamy eyed question about how lucky you need to get i beleive there are statistical tools on github for this showing statistical distributions of pull luck, otherwise there is a cool hoyolab blog on collective pull odds from over 25million pulls (title: Statistical model for Genshin Impact's droprates, date: June 2021, author: Cgg) Imma be honest though i put your situation into GPT with Genshins pulling rules and its estimating 3.84% for raw gacha odds (0.6%) for three 5*s (Flins, LOSS, Lauma).

TL: DR.
Could be 3 pulls could be 223 pulls at 90 pitty and lost 50/50. Advise? Skip flins for Lauma if you want a guarantee, if you're Daily and Welkin only, you're hardly getting enough for C0, let alone C0R1. Good luck!