I've never run across them in my research, I would assume it does since the 8" axle is essentially the same thing on ours since it came out but I'm not 100% certain.
I would be cautious though, I disagree with their reasoning. If the Heims are mounted correctly then the bolt can be horizontal (heim vertical) and all the loading will be parallel with the link, so stating it will increase joint life the way they did it doesn't mean it's not true for other mounting configurations. Additionally, with the heim vertical then the joint geometry if you will (how the ball and bolt are in relation to the race) shouldn't change drastically (if at all) since the bolt is just rotating (when the whole axle droops), so the joint isn't actually deflecting to the sides if that makes sense--which with their setup the joint will have more significant misalignment whenever the axle moves vertically, which would decrease joint life like they argue their setup reduces...
If it was me I would mount the Heims vertical, so then you can droop away and the joint won't bind, so the main misalignment is from one side drooping and the other bumping. With that said, I doubt either one matters and theirs is certainly easier to mount and easy to get the geometry perfect, but if you're going big then a vertical heim setup will only limit flexing versus limiting the whole axle drooping and flexing.
And I don't mean to bash on those guys, I just feel like they are trying to explain statics without fully understanding it... Not to say I'm a professional (yet!)