The whole problem is, at least from what I understand, you can't get a 35 spline D35 carrier. I'm guessing because the carrier journals aren't large enough to support it and have enough meat on them left for bearings after boring them open.
So you're stuck with 30 spline inners, which I can't imagine is that much of a weak link in a front axle on 35s with ~200HP, even with a stick. Outers Spidertrax only makes their hub bearings in 35 spline I'm guessing? So if you want the stronger/more durable wheel bearings you're obligated to go 35 spline, which means obligated to use 806x joints in order to match up with the inners unless you want to use RCV stuff, right?
Like I said, I'd do whatever I needed to to get the Spidertrax bearings. In reality, I think either shaft situation would work out, but having the bearing last a long time is what I'd be after.