IF, and only IF you must stay with a ST tire, Maxxis appars to have the best reputation.
There is however a huge drawback to them. Availability.
This forum is full of threads from those that had to WAIT for them as they had to be ORDERED.
In my mind this is a potential problem. Any tire can suffer damage on the road, and need to be replaced. Even the good ones. Yes the odds are a lot better, but should you need a replacement Maxxis while on the road.... Odds are you will not be able to get one.. You will either have to wait several days, or accept a inferior replacement.
So if you are able, I recommend going with LT tires. They suffer much less from the quality/reliability problems that plague the ST tires as a whole. They do not have the 65 MPH speed limit restriction, and are widely available just about anywhere.
Even if a LT tire should need replacing on the road, and the tire shop doesn't happen to have your brand in stock....They will have a LT tire of another brand that will be perfectly serviceable, so that you can continue on your trip without a tire concern.
Balancing and metal/rubber stems are down on the list as far I'm concerned. Balancing will likely never pay off in tire wear on a TT, and a solid axle won't transmit vibration to the TT like a steering/independent one on a car would. So long as the stems are rated for the PSI, then they are fine. Metal ones will last practically forever, but usually cost more..