These sell fairly well for a low lvl synth, however unless you graden Saruta Cotton, it's difficult to get cheap because of Guild Campers. Secondly, even at 4.6 Clothcraft, these are difficult to make. Capes have better success rate for me, but on the occasion that I do synth a Doublet, the 6k it sells for on Asura is nice.
the level they post is what level it caps at, you can make the item 2-3 levels below it for decent skill increasing also with making the item of course... but for example, the doublet is 5, you will not gain skills for doublet when you reach 5 at least that is my assumption... im pretty sure of this because i KNOW for a fact cape caps out at 8 and it says 8....
Being within 5 levels of a given synthesis you will make what you are aiming for 90% of the time, you weren't lucky or anything, just the mathematics of the synth system working in your favor.
The listed level is either the cap at which you will no longer gain skill, or the "trivial" level (this place doesn't have the best records... go look at skill level 0). THe first is obvious, teh second is when you will nearly neverf fail. Am I right
Ya'll have to remember that which day it is and the moon phase will have an affect on your success rates, skillup rates, and break rates. The specifics aren't ever really clear, and some even say direction will affect it (bowing down to the gods), but you can look that stuff up if you're planning to do some serious crafting.