Weaverbird has been out of commission over the winter, so I haven't been using either the heads or the cooker.
I'm confident that the heads is going to be OK. No, there isn't a stirring device; the idea is to add a handful or two of medium after each use, and that means that a bin of medium has to be readily accessible, as an essential part of the scheme. I haven't bothered with installing a fan so far, but have put a good cowl vent overhead.
I bought an Origo and came to the same conclusion as you after just one lighting of one of the burners. I've made a single burner cooker using a Maxie meths burner as I found this to be an excellent piece of kit in operation and efficiency - but not, as both Annie and I have found, quite so good for longevity. However, I did get several years use from a burner, with no maintenance required at all. The only supplier, Whitworth in Australia, will only despatch to within the South Pacific area, so to get a burner or a complete cooker, you'd have to persuade someone in Australia to receive it and forward it to you.
First, I built this burner into a 22cm stockpot, and tried to gimbal it. This was not satisfactory, and now I have built it into a fixed 18cm pot (no photo). This will take 16cm pans, and is what I will have to use this summer. I have a 16cm pressure cooker, kettle and saucepan.
I've been trying to invent a meths burner that can be made in a home workshop, but with no success so far. This project will have to "go on the back burner" now, as I'm running out of time.