Same situation I found myself in when we went back to a travel trailer last year. I was just over the 650 lb rated capacity of my receiver without WD. Once loaded, I'm sure I'm well over. I bought a Reese HP trunnion style WDH without sway control. Dead weight sets the rear of the truck down 2". I set the bars to raise it back up 1". Front didn't change either way. Tows like a champ. DO NOT load heavy in the rear of the trailer to lighten tongue weight. Always load in front of the trailer's axles and let the WDH do it's job.
For a half ton towing enough to need a WDH, I would recommend the Equalizer 4 point hitch. If you find you don't need sway control, a little light lube on the friction points will quiet it down while still offering a reduced amount of sway control. Just my humble $.02.