My trailer is a 2009 model 29-5T, which is somewhat lighter overall and definitely lighter on the pin weight compared to the 29-5K. I find that when I go out, I'm always over my 9200 lb GVWR by 500 to 1000 lbs or so. The truck is a 2008 Chevy Crew Cab long bed with Duramax/Allison. I have upgraded tires, wheels, added more spring and upgraded the shocks to help carry the increased load. The trailer feels just fine behind the truck, even in gust, windy conditions. I'm very happy with the handling of the combined unit.
Having said that, I would prefer to have a 1 ton vs the 3/4 ton. Just makes more sense to have more truck to handle greater weights. Sure the factories probably under-rate their truck's weight carrying capacity, but you don't want to get too much over the ratings, just in case you have problems.