Tools appear to have nearly double the chance of specs to yield MCDs (according to many other people's research), and when they do yield MCDs, they can yield 1-3 (average: 2). So, that means that while a tool takes 2x the materials as the specs, they yield 4x the MCDs. Tools are the way to go. If you are a BSM desynther, go with the CRP saws (as someone said above, and remember you can buy Aldgoat Horns from the Kobolds and get "free" spruce lumber via LTW desynth if you have it (Bridesmaid's Sandals)). If you aren't, but you're a GSM desynther, go with the WVR needles. If you aren't either, but are an ARM desynther, go with ALC pestles or CUL frypans, whichever is cheaper to make (probably CUL, but NQ Volcanic Rock Salt is dirt cheap, generally).
If you're making HQ Twinthread for the needles, you probably want to sell that twinthread instead. That is not an efficient way to make the needles. What you want is a macro that can yield HQ tokens from all NQ materials, and run that with NQ twinthread you bought off the market after selling all your HQ twinthread. Last I checked, on my server, NQ twinthread was less than half the price of HQ.
If you do not have the stats to make HQ tokens from all NQ materials via a macro, then making the tools for desynth are likely not worth it. Especially if you are not a BSM desynther - WVR tools seem to cost about double what CRP tools cost. Here's the formula (which assumes shards are ~100gil each): [8*({spruce lumber}+3600)] ?= [8*({silver ingot}+2*{twinthread}+2100)], which simplifies into: {spruce lumber} ?= {silver ingot}+2*{twinthread}-1500. Plug your server's numbers into that equation to see which is cheaper. My guess is the Spruce Lumber (CRP tool) by a large margin.
If anyone needs, here is a macro for creating HQ tokens out of NQ materials. This macro is designed for people who are near 4* capability who do not want to pay attention to the craft. It requires at least 428 craft and works best with over 400 control. It takes 394 CP and thus requires HQ Bouillabaisse (but I more than make up for the price of the bouilla by not having to use HQ mats or pay attention).
This is not a 100% macro. I have, however, had very good luck with it. If all HTs succeed, you hit 100%. If one fails, you still hit 100%. If two fail, you hit around 96%. With three fails, you hit around 77%. Four fails will put you down near 29%. Though, if your final BB falls on a Good, you get much higher than that and chances are about 25% of that happening, further increasing your chances. On average, two should fail.
If you throw in one HQ material, it succeeds ~99% of the time (with my last batch, 1 HQ Horn Glue or Spruce Lumber in each synth: 144 HQ tokens made, 1 NQ; also, 18 tools made, 15 MCDs yielded)
----Macro 1----
/ac "Comfort Zone" <wait.2>
/ac "Inner Quiet" <wait.2>
/ac "Steady Hand II" <wait.2>
/ac "Waste Not II" <wait.2>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Steady Hand II" <wait.2>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Comfort Zone" <wait.2>
/ac "Hasty Touch" <wait.3>
----Macro 2----
/ac "Manipulation" <wait.2>
/ac "Steady Hand II" <wait.2>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Hasty Touch" <wait.3>
/ac "Steady Hand" <wait.2>
/ac "Great Strides" <wait.2>
/ac "Ingenuity II" <wait.2>
/ac "Innovation" <wait.2>
/ac "Byregot's Blessing" <wait.3>
/ac "Standard Synthesis" <wait.3>
/ac "Careful Synthesis II" <wait.3>
/ac "Careful Synthesis II" <wait.3>
Other people may have better macros than me, but this is what I use.