How do you get traffic to test?

The best proven way for testing is PPC. It can be quite expensive, though, so you
should be careful with it. Some other ways that come to mind are PPV and banner ads.

I usually use PPC, or if it is a niche that I've already built a list for, I will send out a mailout for my list.

I agree with the other who say PPC.. In fact with every new project I enter, I turn to PPC to test it first. I don't want to waist my time doing all the SEO work and time needed to get the traffic organically to find out the niche was a dud.. I always use PPC to test it first. It's worth the risk for sure.

thanks for the replies, can anyone recommend a good ppc wso?

I agree PPC works well - but to do it right, you use more than one ad (to see what wording grabs folks the most) as well as more than one landing page (to see what really converts).

You can also get a different perspective by using a service like usertesting.com. With that kind of service, you come up with about 15 minutes worth of tasks and a few questions. The people will do what you ask them to do, and you get a screencast of their screen and the audio of them talking their way through what they are thinking. It can give you a lot of perspective into how the page is really working.

You can also ask for only certain people to participate. In this case, it sounds like you are going after internet marketers, so you can request that only insane folks like us participate.

Another option, which also helps you in getting reviewed, is to use the "Wanted - Members Looking To Hire You" on this forum. Ask for reviewers (there's stickies on the top of that forum telling you how), and include your sales materials as part of the review process. The cool thing is that it is only $5. (plus a couple of copies of your stuff) and you will get reviews that can be helpful with your marketing.

Update - sorry, misread your post. Forget the part about insane internet marketers. <grin> In your case you could ask for folks that would like to lose weight.