This is what I was thinking of in previous comment. You end of with 4:1 purchase.. but to minimize friction so it will release smoothly you'll need to use small diameter dyneema single braid rope... 1/8' diameter would be ideal . The forward, handled/cleated section can be regular polyester double braid 1/4" rope. It'll probably work okay with all same size stuff.
But wait! Before you get started, you'll want to get things cleaned up at the end of the boom. The big cheek block in the picture is for your reefing line. Whatever else you have... like that clip for the pigtail...is that blue line the topping lift? if it is... don't wrap it around the boom like that... and also, you don't need that wire pigtail if you have a proper topping lift... so cut the damn thing off. Then start saving for a rigid boom vang so you can get rid of the pesky topping lift altogether.
Okay, sorry about the mini rant... Let's continue.
If you can't find a "lance" cleat... a jam, vee or clam cleat with a fairlead to keep the line captive will work...they're very inexpensive. Like I said, all the friction will be in the back where the line goes through the cheek block up through the clew and back to the eye at the boom end. You should be able to fix the line to the eye with a figure of eight knot, to keep it from pulling through. I would bring the cleat forward about 40% of the boom's length, so you can adjust it when it's swung out on a reach. If you leave it at the very end you won't be able to reach it unless the boom is inside the cockpit area. For attaching items to the boom, I'd use self tapping SS screws that you've dipped in anti corrosive compound for the thin walled boom.
Finally, I just want to remind you that the small line diameter size isn't going to be uncomfortable like it would for a halyard or a sheet where you're winching and hauling all the time. The adjustments are much smaller and certainly not as frequent. The most important thing on a multi purchase outhaul is to reduce friction.
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