I see this goes with your other post concerning bubble count vs. tank size. I posted on that thread that bubble count is a very arbitrary number to use that won't transfer well to your own situation. People have all kinds of water parameters, surface agitation, and CO2 usage by plants that its too varied to apply universally, for example that 30bpm for a 40 gallon. It just won't work.
Sure peat is nice (be careful, terrestrial plant keepers will swear by it) but I think for us planted tank people it is rather too much trouble that the benefits are not appreciable to sacrifice not knowing our CO2 levels. Their are so many tanks growing beautifully w/o peat, I think you can do it too. When the time comes that the plants aren't growing fast, or algae is flourishing - you will really need to know the CO2 levels.
My suggestion, first of all because 1/4" is not thin, but a ton of peat, is to remove it all if possible. I remember rex always said that it should be used very sparingly, like sprinkled on the glass bottom.