Feeding when kept in fridge
I have a starter that peaks after I feed it 1:1:1 within ~6 hours in 23C. I want to stop feeding it every day and start to keep it in the fridge and feed it once a week, when I can also take some to make bread and put the rest back in the fridge.
My concern is that when I feed it 1:1:1, I'm essentially diluting it 1:3. If I put it in the fridge and it doesn't populate, then the next time I take it out and feed the same ratio, it'll become 1:9, etc. So essentially I'll dilute it more and more until there's not enough in a batch I take to make bread (so say I take out 250g, but it has 1:27 of the yeast/bacteria it is supposed to have).
So, what is the proper ratio to feed if I put it back in the fridge every time for a week? How do I know the population of yeast/bacteria is at the ratio it should be? Note that I'm trying to avoid tests in which I need to wait 12 hours or multiple cycles of feeding to know, want something as much hassle free as possible, and still have a starter I can take out of the fridge, let it warm for several hours and start making bread.