So I have a white superior tiara, and tried to use the Ral + Thul + perfect Sapphire recipe, but it doesn't do anything. What gives? Tried to google this but absolutely no hits on this topic.
The recipe worked on a circlet.
Ok, so I read some random comments about something else, and figured that the recipe doesn't work on superior items. Oh well.
I see you found the answer. Indeed you can only use the helm socket recipe on white normal /ethereal helms. Not superior, magic or rare ones.
If you would find a particulary interesting helm you can Larzuk it, but I would never waste a Larzuk quest on just a white superior tiara.