First you need to know your truck's cargo capacity. Should be on a yellow sticker on drivers door jamb.
Secondly, while dry weight is not indicative of real world application, if used properly, you can use it to help. Get the dry weight and dry tongue weight of both trailes. Add roughly 1000 lbs to the dry weight. Multiply by 13 percent to roughly determine tongue weight the trailer may be at fully loaded, ready to go.
Take this rough tongue weight number, add weight of passengers and anything you plan on putting in the bed of the truck. If that number exceeds your cargo weight of the truck, the trailer is too much.
I suspect both trailers are going to be too much for your V6 truck. 28ft trailer is larger than what I was towing with my Sierra 1500 with 5.3L V8. I was towing a 26 ft trailer, loaded weight approximately 6500 lbs, and I really didn't want to pull anything larger with it.
Good luck
Mike