Appeal and Source setup for testing offers

Hi all,

I'm doing my inaugural offer test in Tessitura!  I'll be splitting the group in question into 3 segments using an extraction; 1 segment will get a postcard, 1 segment will get an email, and 1 segment won't get anything.  Then the results testing shall begin!

I'd love some recommendations about how I might set up my appeal and source structures.  Here's my current plan, along with my questions:

One appeal for all 3 segments (obviously).

Appeal Category: Member Offers (meant to be used for either mail or email into the future).  Does this make sense?  Or is there a better way to do this?

Source group: One for each segment: Direct Mail Offers/ Email Offers/ Control Group - No Offer.  Again, make sense?

Media type: One for each segment: Direct Mail Jan 2011; Email Jan 2011; Control Group Jan 2011.  This is a very specific approach; would I be better off doing a more general "Direct Mail, Email and Control" set and re-using them in the future?

Thanks everyone - I want to make sure to do this right!

Beth