I had a old style Reese with the spring bars that had the chains and it adjusted tension by moving up or down the chain links. I had a separate friction sway bar. The system lasted 10 years (2 trailers). The 3rd trailer ended up actually bending the hitch head. Although the ball on the hitch head was more than sufficient for the heaviest trailer, the age, wear and tear and extra weight of the last trailer ... well ... it only took one 1600 mile trip towing and I had to replace the entire system. I went with a 1400, 14,000 Equal-i-zer Four Point with built in sway. It was a good move. Once the hitch is set up right, it's extremely easy and fast hitching and unhitching.
My suggestion, if the old system is going on 10 years old and it's towed faithfully all this time, it might be time to switch to a new one anyway. This way you know the weight ratings and not guessing, and the old one does have 10 years of wear and tear and fatigue. With a heavier towing challenge now, it's subject to failure. Don't make the mistake I made. Although, I caught my fatigued hitch system before it bent so much it was dangerous towing.
Good luck! My advise... get a new systems now, retire the old, use it for a door stop in the garage now. That's what my old hitch head is used for now.