I posted most of this in the Alexander section so I will gladly say it here too.
First off there is one word which one must know before undertaking HQ synthing. And that word is: RANDOM. Also, there are a lot of theories on a lot of things and I will discuss what I believe to be correct. (But like I hinted, nothing is concrete; there is no sure fire formula to make an HQ.) Another thing is that there are a lot of things that go into a HQ product.
First thing I wish to discuss is regarding HQ and skill level. This was said by Eruntalon on good old Allakhazam, "It is rumored that the HQ chance is not linear, but is actually tiered. It is further rumored that there is a maximum chance that hovers somewhere around 50%."
In my experience, I can attest to this. (Even though I do not consider myself a great crafter.) As a smith I spend most of my time making consumables (faster sell and better ROIC). I have made several hundred Bronze Ingots so far in my career as a smith. Bronze Ingots cap at smithing level 2. The number of HQ synths I get at my current level (23) and the number I got as a level 2 smith are very comparable. At both levels I get about a 2-3% HQ rate, even though I am 21 levels higher than the cap.
Now yes, I know what you are thinking, "But Dukuji, there is no HQ product for Bronze Ingots." This is true; the HQ of a Bronze Ingot synth is a Bronze Ingot. But, I know when a HQ happens because I get the special little HQ animation. (Looks like the Death Star blowing up and sounds like something getting sucked up a vacuum.)
Now, let us consider Iron Ingots. Unlike many other types of ingots, Iron Ingots do have a HQ synth, a good one at that too; the almightily Steel Ingot. (Worth at least double the price of Iron Ingots.) It's for the chance of obtaining a Steel Ingot that all those desynthers buy the lightening crystals and beastmen armor pieces. Anyways, I'm a smith, not a desynther, and I have made several hundred Iron Ingots. The skill cap on them is at 20. At level 23 I get about 2-3% HQ synths off of Iron Ingots. It is interesting to note that even though I am only 3 levels above the cap, I've had about the same amount of luck getting an HQ off of an Iron Ingot as I've had getting an HQ off a craft I'm 21 levels above (Bronze Ingots).
If the chance of a HQ is linear, like commonly believed, then I should see a significantly larger number of HQ with the lower level synths then I should see with synths that I am at a comparable level with. To me this suggests that perhaps there is a tiered system involved with synthing. I saw a level 50-something smith sit down and start making Iron Ingots but, about 25-33% of them where not Iron but Steel. After talking to him he said that around smithing level 50 you will see a sharp very sudden climb in the number of HQ products in several crafts.
It is wise to note (although I cannot verify this through my own results) that many crafters believe that to obtain an HQ on a regular basis you need to be about 30 levels above the skill cap level. Like I said, I can neither verify nor prove this to be invalid. But like the level 50 some smith that was making those Steel Ingots he was about 30 levels higher then the cap.
Okay, now regarding days to craft. Many crafters believe that the best days for HQ and skillups is on the day the crystal is weak against (in my case fire is weak against water, so Watersday) and on Darksday. Many also believe that the best day to land a synth but have less skillups and HQs is the day of the crystal, the day the crystal is strong against (in my case Iceday), and Lightsday.
When I do get an HQ product I've noticed that when I'm using Fire crystals, I'm more likely to get a HQ on Darksday and on Watersday but, these are they days that I have more synth failures (even on the Bronze Ingots). The days I have the most success making the synth but not getting a HQ have, so far, included Firesday and Lightsday (I haven't kept track of Iceday so I can not say either way on that one).
There is also a theory on which way to face while crafting. I am currently running tests on this and do not wish to comment on this at this time.
Now, remember, this has been my experience and it is very limited to a handful of synths that I have repeated many, many times and only in one craft. And again, as with most things in this game, luck seems to play the largest role.
Good luck and happy crafting!
<== Glasses on for safety
