Found your article in mid December and gave it a try. I had in fact just ordered a twenty day supply of Augmentin which is still on the shelf. Anyway The first couple of times I did use too much Hydrogen Peroxide and my sinus snapped shut that night, but eased in the morning. Didn't take but a couple of rinses and I was feeling better and that late afternoon fever was gone. I have been laying on a bed with my head tilted back, but I think your posture may be the best as I don't think my front sinuses fill with the head tipped back.
For what it is worth, I use pure preservative free saline from an aerosal can for soft contacts to make my mix which can be had for about $2 for 12 ounces and is already pH balanced.
So thanks for your post, it seems to be doing me a world of good.
I need to go look and see how many ounces of liquid the sinuses can hold, mine don't seem to hold very much, but boy have they caused me problems....