Once the basic circuit was up and running, earthtones helped me refine it and make it much nicer. He's wicked smaht like that.
Delay time range is about 40ms up to about 140ms. As delay time is increased, more highs are rolled off by C4 (that was ETA's idea). So it's pretty much hiss/noise free no matter the delay time.
He posted a demo here, and it sounds pretty good to me. Something different to do with those PT2399s you've got.