Hi Tom,

Yes, I have to agree with Jennifer.

AdWords is great method of testing conversions for your actual site.
However, you take into account that these conversions may not
neccessarily reflect the conversions of a JV, as you are sending a
solo ad (email), rather than a cpc ad.

Definately keep testing with AdWords - I do the same all the time.
Although, you can and should test conversions of your solo ad(s).

I like to use Rent-A-List.com for my split testing needs.

To your success,
Sean