What you need:
Oversized shackle (some use quick pin, but I learned that a shackle is more secure)
Loop spliced into Downhaul
Once set up, You’ll be quick to rig and unrig and you never unrig your down haul.
attach boom to mast and sail
shackle vang to mast tang
Connect vang to boom
Pass downhaul line through sail, clip in your loop
Opposite to unrig, be sure that you don’t untie your downhaul, and leave the system on your cockpit
Disclaimer.....This will make it simpler and faster to rig and unrig. Unfortunately doesn’t make you faster on the course.