Do you have anti sway bars? This will reduce some of the "floating" and trailer swaying sensations you might be experiencing. Air bags are also another thought to consider.
Although we pull a fifthwheel, we found many RV and truck salesman trying to sell us something we did not need. I found the truck saleman to be woefully under knowledgeable when it came to weights and towing data.
RV sales people will always tell you that the vehicle you currently have with EASILY pull the unit they are trying to sell you.
I suggest the best advise is to get with someone who has a similar unit and similar tow vehicle and talk with them.......There are to many so called experts out there who will offer their advise as gospel. Research online and watch for responses here.