I have a loose foot main with a 4:1 outhaul and use this fairly often. The 4:1 part works nicely but I wanted to improve the cleat so messed with this yesterday in the back yard. At one time I had ran the outhaul line back to the mast, down the mast, to the cockpit but I just dont like all the rigging hassle (personal preference..) so moved the outhaul cleat back to the boom. Pictures below tell the story.
Picture below. This is the change I just made. This is on the underside of the boom and when you need to tighten the main in high winds, there can be a bit of force involved so I wanted a nice fair lead with a direct mounting to the boom. The cleat is behind the fairlead which isnt completely optimal but the other way around causes some issue releasing the cleat. Anyhow.. this is what Im going with at least for now. The line out of the fair lead heads towards the back end of the boom.
Picture below. This is the part of the outhaul that works fine - been using it for a long time. It has 4:1 leverage.
Picture below. This is where I have the cleat for the outhaul (black arrow). This is the old cleat in the picture and the new one is just slightly aft - but essentially in the same spot. Having it on the boom makes rigging the boat easier since its always already rigged. If you put the cleat too far back, it can be hard to get at if the sail is sheeted out. Too far forward and you have to go too far forward to get to it. This spot works OK especially since I sit fairly far forward in the cockpit for sailing (tiller extension very often used).
Picture below. This is the cleat I just removed. Mostly worked OK.. just enough hassle to use especially when its windy single handed that I decided to try and improve things and get rid of this.
Picture below. This is an option I did NOT use. Its a standard high angle fair lead with cleat. It may have worked fine.. but I wanted a more robust fair lead and better leverage since you are going to be pulling the line down - and sometimes with a bit of force when tightening the main in higher winds. FYI, this is the furler cleat on my Hobie TI - shown upside down.