What method for advance prep of seitan prevents deterioration of texture and preserves flavor while protecting from spoilage?
hmm....

my thoughts:

1) biologists use stock as a medium for growing bacteria.  therefore, anything stored in stock; I generally like to boil/heat up a lot first before eating

2)the seitan should stay just fine; kept dry in the fridge in an airtight container

3) have you tried making steamed seitan, ala seitan of greatness from lachesis?

4) have you tried making "dry" seitan in a water bath (bain marie) in the oven: this is how it is done in the rfd (real food daily) cookbook. I make this a lot; both the "chicken" and "basic" (which reminds me of turkey)