Consider running the downhaul
line from the block at the tack directly back to the cockpit on the centerline of the boat and then to a cam
cleat to keep it tidy. You could run it through a cheek block on one side of the mast or even on deck to keep the run straight.
Spectra or Dyneema are great here because they can be quite thin and still do the job without putting weight and tangles aloft.
An idea I had to "improve" a
jib downhaul is to make a rather large loop. Put the top of the loop through the headboard or through the
jib halyard
shackle and run either side of the loop down to blocks either side of the forestay. When you pull downwards, the pull is even either side of the hanks, and so the chance of snagging is lessened and the speed of the drop can be controlled by easing the halyard at the desired speed.
I came up with this idea while contemplating putting reef points in my staysail.