I suggest visiting Mithrie Menethils's site or Ashe10's site.
I used quest gear and just crafted the HQ level 55 set slightly melded only in the guaranteed slots (it was cheap because I already had them) and then made the level 60 HQ set and overmelded them to 2 star.
Definitely level them all together so that you can share gear and make mats that you will need for progressing.
One thing they really did in the expansion is make you dependent on all crafts to get buy...so you will need to level them all or spend a lot of gil. I also recommend that you level your gatherers at the same time or you will be spending even more gil.