OK so I found the only piece of actual info from SE on this subject, take from it what you will, Im sure ppl will still argue

Personally I always get tier 3 support for HQ synths, and at least tier 1 on harder grind crafts (like if its 10 ranks above mine)

just go down about 1/3 of the way to "synthesis facilities"
http://lodestone.finalfantasyxiv.com...e/craft01.html