I look at the UVW, GVWR and CCC. I know what I can tow, I know what I carry and I know how much in reserve I want. If you know all that then it doesn't really matter if you're maxed out after loading or still have 2-3000lbs left before reaching the trailers GVWR.
My 5er has 4315lbs of CCC. I only load 1500lbs max in it. It also has a GVWR of 11,400lbs. If I used the GVWR I couldn't tow it because my truck doesn't have the payload capacity since the pin would be around 2200lbs. I only have 2176lbs for payload in the truck. However it only weighs 9000lbs when loaded and has an 1800lb pin. So for me if I used the 5ers GVWR I couldn't tow it.
The reason people say to use the GVWR is to take the guess work out for newbies.
