I've been making bronze spears since I discovered the recipe at about skill 12. With synth support I gained pretty well off them. At about 14 I started failing a fair amount (mainly because I went off image support by then) but after gaining to 15, suddenly I was succeeding all the time and gaining off practically every synth.
And the best part is, these are really profitable! Here's how the pricing looks on my server:
Ash Lumber (wood guild): 160-180 gil Bronze Ingot (smith guild): 150 gil Grass Thread (Selbina weaver guild): 45 gil Wind Crystal (AH): 100-150 gil
High end of cost to make: 525 gil Lowest city's current AH price: 1000 gil Usual AH price: 1300 gil
So yeah, doubling your money on the successes while gaining skill like crazy sounds like the win. They tend to sell really fast, too - often when I look them up on the auction, there are none for sale. I definitely intend to make these to as far as I can gain on them.