Bonjour nonparagon,
The important thing is to have one basic position that will be used when you set the enveloppe. This pose will normally fit your enveloppe object.
In my case, I build the rig, and store the skeleton pose for all control objects and bones that rotate. Then I set the enveloppe, and start weighting it. During the weighting process I define other poses, like a "crucifix" (I model my character with arms at 45