which makes setting up the Hobie 16 for racing so challenging.
And then adding or releasing downhaul also changes the rig tension by bending the mast, adding another element of challenge (read fun) to getting it just right...
I also think whether your weight is on the trap wires or not also has some effect..
What I have seen from most new 16 sailors, not only including, but especially myself is that the downhaul and the Jib halyard tension simple get set on the beach based on what the book says, or what they heard from some 'fast' skipper, and then they go play all day only playing the travelers and the jib and main sheets... Once you have a basic feel for the boat and how it is responding playing with those controls (jib halyard and down haul) generally make pretty obvious changes.
IMO one of the best things I have done is spring for the Hobie 6:1 down haul setup with the cam cleat, and then the Aussie jib halyard setup with a couple extra blocks at the bottom of the mast turning it back into a cam cleat before cleating it off... Both of these make it REALLY easy to make small changes quickly and feel how the boat responds. I can't and won't tell you I have mastered it, but it sure makes things easier to learn..
You don't need the fancy hardware though... So don't be afraid to play with those lines... It is pretty easy to adjust jib halyard tension running downwind no matter what setup you have...
Oh... and on my boat.. I have a piece of electrical tape wrapped around the jib halyard... and a Tape measure stuck on the mast.. I try to not get to caught up in in exactly setting it "to a number" but instead it allows new crew and often me to have a guide to know where I started and where I moved to on any given day.