More easy is to turn the boat head to wind on the beach (or on the water) and pull the mainsheet tight and only then pull on the downhaul. The mainsheet will bend the mast to a large extend making it FAR easier to pull on the downhaul and cleat it. Then release the mainsheet and the mast will stay bend (as you want) and you are ready to go of to some heavy wind sailing.

No expensive cleats needed for this. I use to preset my downhaul on my 1974 Prindle 16 that way and it used a horn cleat and only 1:4 purchase.

Wouter