TWW ...get a Oz or just an eighth?

I’m 6 dpo ... and I have huge doubts it worked this month.

I usually go though an eighth throughout the week and another eighth on the weekend.

I’ve switched from joints to bowels while I’m TTC so an eight last me a while that way..but the weekend is coming up and it’s time to reup...

Should I continue the small bowls and just get an eighth or should I get an Oz?