Well after the whole drama with the website design, I'm not overly optimistic about the design of a complex trading system probably created by whoever made the current ActM website.
I think the best option would be to go direct shares (though it makes liquidating shares more difficult), and hire someone to manage this if required.
You've seen this, right? http://mpex.co/
LOL. I think we can at least hit a slightly higher mark than that.