The Reese Pro series is the "economy" 5er hitch from Cequent. Don't buy that one.
For your 5er weight, you want the Reese Classic Series, sometimes called a Reese 5er hitch. The 16k max trailer weight should be plenty, but it won't hurt to spend more and get an 18k or 20k hitch.
Note that hitch has the rails in the bed. When you remove the hitch, all that remains in the bed is the two bed rails, that are about 3/4 inch thick. If you tow infrequently and hate having those rails in the bed, then it requires about a half-hour to remove them, then another half-hour to replace before you tow again.
I had those bed rails in my bed for 12 years with no problem. But if you must haul pea-gravel or sand in the bed, then you'll probably need a bed rug over the bed rails, or else remove the rails after the hauling job to get rid of the sand or gravel in the cracks and crevases in the rails.
There are more expensive 5er hitches available that leave nothing in the bed but some holes covered with plastic covers. A popular one is the B&W Companion, which plugs into a B&W Turnover Ball gooseneck hitch. So install the TurnOverBall, then Companion.
Amazon.com: B&W Trailer Hitches 1067 Gooseneck Hitch: Automotive
I looked up your previous posts to determine your tow vehicle, but all you mentioned was a motorhome and a toad. If your tow vehicle for the 5er is a late-model Ford or Ram, then a factory option was the Reese Elite 5er prep kit. In effect. that was the install kit for the Reese Elite Series 5er hitch. So if you have a late-model Ford or Ram, and want below-the-bed rails for hauling the 5er, then you can buy that install kit and add the Reese Elite 5er hitch to plug into those below-the-bed rails. With that hitch, nothing is left in the bed except some holes covered with plastic stoppers when you remove the hitch. The Elite hitch comes in two versions, 18k and 25k. For your trailer, the 18k is more than enough. Here's the 18k:
Fifth Wheel by Reese for 2013 F-250 and F-350 Super Duty - RP30142
And here's the install kit (under-bed rails) for a late-model Ford:
Under-Bed Rail and Installation Kit for Reese Elite Series 5th Wheel and Gooseneck Trailer Hitches Reese Fifth Wheel Installation Kit RP30126
Reese now makes the Elite 5er hitch for several older models too The hitch is the same, but the install kit is different, depending on the make/model/year of the tow vehicle.