I am having to look at the pictures on my phone, so I may have missed something, but here is my take on it:
I don't think the leveraging arm will have any reduction in the pull on the guy-lines. Overall, the stand has to over-come the compression forces along the top of the hammock and I don't see anything in that leverage arm itself that will reduce that.
The main difference between this and using one end of my stand is the extension legs (and that is huge). They will impact the pull on the guy lines by counter-acting against the leverage of the pole.
I do see the leverage arm having an impact on the strength of the forward extension leg. However, I would be careful of the connection point for that arm as it will have a tremendous amount of stress on the pivot point. It could very easily snap right there. Personally, I think a hard connection for the support, instead of a levered arm would work just as well.