Any thoughts on promoting and selling an investment newsletter?

I've made money online with adsense and as an affiliate, but now I have an idea for my own product, trouble is I don't know how to go about promoting it or even the logistics of actually selling it. So I was hoping my fellow warriors could help!

Product
I'm looking to sell my stock investment advice. The way I figure I'll do it is to sell subscriptions to an email newsletter that details the investments I'm making and why. These emails will be sent out as I enter and exit positions so subscribers can easily follow along.

Experience
I understand that this type of newsletter lives and dies by the performance of my own investment portfolio. That portfolio and its historical track record is the main selling point, when I'm having a particularly good month I'd expect conversions on the sales page to be high, while during bad months not so much. I have an 18 month track record of consecutive profitable months with varying ROI.

Competition
Nearly everything I've seen in the way of competition is pure BS. Many people are selling these kinds of newsletters based entirely in hypothetical portfolios. They've never actually invested in the open market. Those that do claim real track records are usually for tiny sample sizes (a handful of trades) where they happened to have several successful trades in a row to make it look like they never lose.

As a result most sales pages and promotional tactics are so ridiculously over-hyped I gag while trying to read them. If it can be avoided while still being successful I would prefer not to have to use that stuff.

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I think that about covers the 'what'. Now on the the 'how'. This is the part I'm fuzzy about.

Delivery
I figure I'll use an email marketing platform like aweber to handle the subscriptions and delivery of the newsletter. Any other ideas? It doesn't have to be a email newsletter, I mean it could be a membership site or something too.

Sales
How do I go about actually selling the subscription and collecting the money?

Promotion
The simplest approach I can think of is to buy traffic directly to the sales page. I've never bought traffic but I'm guessing buying ads on investment forums and solo ads in other related newsletters would probably be the best. I would think PPC would be very expensive for any keywords remotely related to this niche.

I could build a site with niche content but I doubt I could say anything that other's don't already say better. Besides, my system is pretty simple, I honestly don't know how much content I could produce on the topic without being either too generic or explaining the whole thing so no one would need to buy my newsletter!

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So I think that's it, that's what I've been able to come up with, and the questions I have. Thanks in advance for your thoughts and ideas.