I think that your 5 email technique may not be aggressive enough. Using a combination of soft and hard sells throughout all of your email correspondences will likely create better results. You are right to want to build a trusting relationship with your readers, but you can also do that by giving them useful information along the way, so they look to you as an expert in your field.

I recently discovered through a study that readers who do not purchase a product after the first sales attempt, will commonly need 7 - 10 additional correspondences to make a purchase. So, if your readers do not buy your product within the first 5 emails you described, then do not give up. Keep increasing the number of emails you send, use interesting information and a clear ‘call to action’ until you achieve the results you desire.

Recently I began implementing the same system that you are describing through Adam Short’s ‘Niche Profit Classroom’. ( http://1000k100days.com ) In the course we learned how to pick a profitable market with little competition, find highly searched low competition keywords, build an effective squeeze page, generate free traffic streams through search engines and social media, and how to effectively write sales letters and emails using Aweber.

The most relevant part of his course in relation to your question is his email mini-course technique. For many of his niche websites, he uses a squeeze page and free email mini-course as an incentive to capture leads. Throughout the email correspondences, he offers resourceful information about the topic, (ex. betta fish care), while promoting a product using tested soft and hard sales techniques.

As for tracking sales, if you decide to promote products through a site such as clickbank, you can create tracking links that will allow you to monitor when sales are made, and what site they were generated from.

I hope this helps, and I would highly recommend checking out Adam’s system http://1000k100days.com . The course is very detail oriented and will extensively cover the questions you are asking, better than I can answer them. Good Luck with your sites!

-David
References :
http://1000k100days.com

You should build creditability and trust in your emails. Long term business means refocusing your attention back on your customers. Your follow ups should never end. Building repeat customers and referrals beats a one time sale hands down.

If you need higher lead conversions and better customer retention on your products with repeat business just let me know. There’s far too much attention on the lead and not enough on the sale. Hope this helps.
References :
http://HelpingIndependentEntrepreneurs.com

http://www.e-goi.com/ultimas-noticias-de-marketing/e-mail-marketing-pode-beneficiar-do-sem-/mc_doc_pt_893/
References :
http://www.e-goi.com/