I had a very good conversation with Aaron today where he explained to me whats going on.
The issue with preloaded nuts isn't the weight of the head. The reason people install the gas springs is when their motors are too weak to lift the head which is not an issue with the IH kit. The issue is when machining thick amounts of material you may WANT more than 600lbs (the load limit of the spring) of force pushing down. So if you want more than 600lbs pushing down the heavy head actually helps, lol.
He also explained that the backlash could be anywhere from 0 to 0.002 but that he always puts the outer rating on his website. So my backlash might be much less.
Adobe - Thanks for you help and suggestion. Aaron actually does use oversized balls
but I'm not sure if its in your configuration.