Gianna Borgnine’s Metareality Podcast covers information on the Mesh Deformer. Since Karl Stiefvater (RL) or Qarl Fizz (SL) and formerly Qarl Linden is the maker of the Mesh Defomer, this is some of the best information we are going to get. The discussion on the Deformer is the first thing up.
As always I am paraphrasing my take on what was said. I try to get it right. But, listen if you are into the nuances. See… er… hear: Alternate Bases.

01:30 Mesh Deformer Discussion starts.
Basic discussion and thinking in the community is that mesh clothes will have to be built to the Default Avatar. Some people consider that the Ruth/Roth avatar. But, there are a number of shapes that people consider the Ruth/Roth shape. It gets confusing. See Deconfusing to sort it out.
02:48 Karl explains that the best shape is the Default Shape. The default shape is what one gets when they create a new shape in the Appearance Editor. Creating a new shape makes a shape that is the Default Shape. Provided you make no changes to any of the sliders, this is the shape the Deformer bases its calculations on.


