A toy hauler typically has a heavier pin than a normal FW. The reason being to offset the weight in the rear garage. The TH will be closer to 25 percent of loaded weight. You already know to weigh your trucks rear axle, with truck loaded to hook up and go. If the R axle weighs 3,340 lbs, with hitch weight added, you'll have 3,000 left for pin wt. This means that at 25 percent, you could hook up to a loaded to go TH weighing 12,000 lbs.
We don't know what you will put in the garage, or in the rest of the TH. The pin wt can change accordingly, and no one knows without weighing the loaded TH too.
I would say you could buy a TH with a GVWR of 14,000, but not load it to the max, or to stay completely safe, buy one with only 12,500 GVWR, that you can load to the max.
Lots of opinions on a forum, and they will vary.
Jerry