Brett,
You've probably already got this covered, but make sure you've got the threads of the spindle bolts nicely lubed up cos when they're getting tight, the friction between the threads on the bolt and the threads on the inside of the spindle can get real high.
At the same time, if the drilled and tapped (threaded) holes in the spindle for the bolts are too full of grease, then you'll get what's called a "hydraulic lock", where the free area inside the spindle below the bolt is filled with grease with nowhere to go, and that bugger of a bolt will never tighten up no matter how big a torque you put on it.
This may be way off, but it's worth checking out in there with an old spoke or something.
Brian.