Rear Shocks For A 85 Fxwg With Belt Drive

I was just wanting to know what rear shocks would be best to run on my 85 widwglide. They came out with 12 inch shocks but when me and my wife ride with the correct shockes it seems to eather grind the pavment when going around corners or bottoms out on the bottom of the fender if we hit a very big bump. I weigh around 290 and the wife around 140 with the saddelbags full on a trip we would probly be around 600 pounds loaded. any ideas. I found a set of 14 inch progressive shock they seem to do the trick but it feals like im riding a dirtbike when Im up that high.