Quite a few posts to read through so hope this wasn't covered already. I've improved my IPA's in two ways and wanted to share in hopes this may help you:
1) I've moved my late addition hops (5 - 0 mins) to a steep during cool-down. Myrcene, a major oil in American hops and supposedly...
I ran through an O2 tank from Home Depot a few months ago and had to replace it. I believe I got around 18 ~ 20 batches out of it. If you run out sooner (say 12 batches or less) you are opening the valve too much or leaving it on too long.
Sam Adams Alpine Spring is all Tettnang... to give you an idea of its profile. You can also use a Kolsch yeast to get closer to a "Lager" style if you can keep temps around 60.
There are a few threads about this, but I personally have not experienced it. I do between 60 and 90 min for my recipes and don't adjust that just because I'm using Pilsner malts. An open vigorous boil seems to be enough at 60 but it certainly doesn't hurt to go longer. I've always wanted to do...