Steven,
I have a suggestion. Run a load of heavy cottons (towels, for instance) through a wash cycle with hot water and a water softener like Calgon.
This will rid them of residual detergent and give you a working index for judging what is too much and what is ok on detergent level.
Living between both cultures, I have to say that I am still not all that crazy about American HE detergents. I think they are overpriced and not really fully adapted.
Contact a Miele or BOSCH dealer who sells European Persil or similar. I know it is outrageously expensive, but buy the smallest box possible and give it a try. Personally, I would take the "Vollwaschmittel" and not the Color variation. American versions of our washers use so much cooler water, even for "hot" than we do that I don't think the Color variation will produce the results you want.
Oh, to answer a question you asked prior to purchase. I have always had Miele or LG. LG was rated better for pet hair the last time I bought a machine, so that is what I went with. I would not wish LG on anyone in the US; here they take care of their customers, there they shit on them. My experience with Miele has been very good. My last Miele is still running, I gave it to friends. Now in its second decade, it has only had one repair...and that was their fault, not the machine's.
Over here in Germany, Miele is more expensive than Bosch, but nowhere near the price it is in the US. It's the snob appeal, I guess. Over time, our consumer guides rank the machines more or less thus:
Miele
AEG
BOSCH/Siemens/Constructa
and then everything else.
If you ever get a chance to pick up a used Miele, do. If the cesspool problem is that bad, why not go for the grey water solution. That is legal now in Long Island, no? Thought I read something about that a while back.
In any case, BOSCH is a good choice, 10000x better than anything built by Whirlpool.
Oh, Funguy...just a commment. I, too, get super-duper excited about some topics and regularly get slammed by the UK folk for it. Maybe you should try toning it down just a bit? I base my comments on having worked in the used white goods business, selling new Mieles/AEGs and having worked both with Bauknecht and B/S/H...there is nothing wrong with being young, you'll get over that...but really and truly, since the rest of the world has been using FLs for many decades, and we don't all have them anchored to 15" steel reinforced concrete pads, maybe you should read up on the advances in fuzzy logic and solid state electronics over the last fifty years or so.