Thanks Greywolf, I think I'm just overloading the spring rate loaded, easy sorted with a heavier spring, but I do feel the need to adjust comp damping when loaded to be honest too.
I will budget in an upgraded shock, but do like the idea of being able to adjust the headlight more easily, so will look into fabricating something up.
I'm riding solo on the 16th click, fully loaded and with aunt Sally I'm on the top two clicks of preload, and it's wallowing a little, and sitting down on the level.