Well, problem solved! Kind of... I ordered a discontinued atty about a month ago and it finally arrived yesterday. A digiflavor Pharaoh. Been using it since yesterday evening, and all day today (even at work in my pocket, using on and off) and I haven't had any leaks yet, despite multiple refills. Think this is gonna be my new daily.... even if it is a bit big. They have a mini version too if I can find it, which excludes the top AF. I don't much like using the top AF on this one as it is... it's perfect with just bottom AF. I think a large part of it is having the JFC ring which allows me to close it off when not using for a while. Or, maybe it's just a better design...
Anyway, I did add more wick to the Intrepid and so far so good, but only time will tell! Tbh, I think I just needed more trial and error time to get the amounts of cotton right. It's easy enough on paper to understand but it definitely does take a bit of getting used too.