Let me know if you want to take a look at this. Do you still have your open deck trailer?
I wouldn't get a 28' bumper pull. You have to put way too much weight on the trailer axles (as opposed to a gooseneck where you can put the load over the truck). The overhang (from the rear axle to the rear of the trailer) is super long on a 28' bumper pull, which you will end up dragging in parking lots, gas stations, etc.
Special Thanks and Recommendations to;
PAC Racing Springs
Joint Clutch and Gear