I have all my other crafts at level 50... so sitting down and mass producing HQ mythril ingots from Goldsmith and HQ cobalt ingots from Blacksmith was really easy.
These were leve turn in items for Armorer and I got about 64,000 EXP per mythril ingot and over 100,000 EXP for 3 cobalt ingots -- which was also a triple turn in leve. With a stack of about 72 HQ cobalt ingots I prepared in advance, I literally went from level 45 to level 50 Armorer in a matter of minutes.
This.
I actually discovered it by mistake when doing a Culinarian leve early on. In v1 we couldn't turn in HQ items on leves so I was actually disappointed when I got an HQ result... but I realized it was highlighted as acceptable on the turn in, and that's when I found out we could get 3x EXP for HQ items.