After cleaning a bottle, what's an acceptable amount of leftover StarSan bubbles?

Question

I've been slowly improving my bottling, thank goodness. I make a pot of warm / hot StarSan, and fill each bottle with the mixture, then after a while, turn each bottle upside down in the StarSan pot. Then a few minutes later, I drain.

So far, I have ended up with a dense layer of small bubbles, about 1-2" high, at the bottom of my 750mL bottles. I know that leaving some StarSan behind is OK, but I wonder if I'm not doing a thorough job of draining? And if not, how do I get a clean drain without rinsing?

I found this question and answer about bottling, and this answer about foam, but I feel like it doesn't quite answer my question. Perhaps I'm being paranoid, and should just relax and have a homebrew?

Edit:

I wrote this question immediately after cleaning my bottles today. Ten minutes later, the foam has settled down to about 1/2"; much less.

Answer 1

Don't worry about the foam, as far as I remember Charlie Tally, Head Chemist at 5 Star, has said that the starsan is broken down by the yeast. Also, when you fill the bottle most of the foam comes out as a "StarSan Worm", so there's relatively little left in the bottle.

If you've not had any problems with head in your beer then your existing methods are working fine.