Hi Andrew & Petra,
We bought our code sail from Rolly Tasker sails who were brilliant to deal with. It’s more of a cruising sail rather than a “Code Zero” and for this reason were recommended to stay away from the “top Down” systems for cruising purposes.
On their suggestion we went for a Sveggen Furler 375R system and it has worked faultlessly for us….. (read as “me”). It’s a lovely piece of engineering and the only time we have had an issue was due to user error rather than mechanical. If dead downwind it can twist however about 10-20 degrees up there is enough pressure in the sail to hold a shape while not making it too difficult to furl by hand. This also results in a nice tight roll every time.
If we meet up this summer you are welcome to have a look at it over a beer or two.