Stripes, wrap samples and the Golden ratio

I'm doing some guest towels.

I want to add a stripe of plain weave.
How should this stripe be.
Where should it be.

Then the math-geek replies: the Golden Ratio.

The golden ratio has fascinated Western intellectuals of diverse interests for at least 2,400 years. Wikipedia.

As you can see above, I had to Google and I found a formula.

The calculation gave me a stripe 5 cm high, 8 cm from top/bottom.

I took my yarn and cardboard and vent to my Yarn-pusher. She has knitting party in the garden during the summer  It was rather cozy, sitting fiddle with the wrap samples and talking and meeting new people.

Then it's time to choose.