Looking for input on setting up rollers on extend a hitch

[Irishman]

After nearly a year of loading and unloading my xfactor onto my roof rack and needing the extend a hitch in vertical position for stability I'm looking to install rollers on the hitch. I figure this will be the easiest way for me to load and unload solo as opposed to waiting for some unsuspecting stranger to be roped into giving me a hand. I have tried the horizontal approach but my truck bed is only 5' and there is way too much play / slop once I have it tied down. Using the hitch vertically allows me to use the existing roof rack for more stability and still have the space in the bed. Has anyone mounted rollers to the hitch? Advice on installation photos much appreciated. Lastly if anyone has any used rollers in good condition they want to sell let me know. Kayak is xfactor, located in San Diego.
Cheers!