1650 + hunt deck gator trax with a 36 hp pro drive = 24mph with 2- 170lb guys and a dog. 3- 170lb guys and 2 dogs 22mph. Turns on a dime. Rpm is around 3800/3900 wot with both loads. Idles in Gear around 800.

So far I am very happy with the boat and motor but it seems my light load should be faster?

That sounds about right with that boat. I'm assuming total length of the boat is around 18' with the hd? If the boat was a square chine you might pick up a little speed with a load because the round chimes don't carry extra weight as well. Also I think your RPMs should be more like 4000-4050. Either way you're not too far off. Empty boat you should be around 27.