Not much point in going after master in any craft without all of them leveled to 50. Every single one of them offers cross class skills that are essential if you want to HQ with any reliability, which you will need to do to make the untradeable items for your crafter of choice's artisan stuff.
However, as you've realized, leveling them without leves is super duper slow. So I would actually take it easy and use your current gatherers to make you some money, or join spiribonding parties (or both) to earn the materia you need for the crafters/gatherers you want. Things like Ore on miner and random botanist things can add up to some nice gil over time and are always there to gather. Once you can go after one star nodes, there's clusters, Dzemhel (sp?) tomatoes, Gold Ore, volcanic rock salt, and so on, all of which will earn can earn 100k+ a day easily from gathering them a few times a day. You'll get into a routine and start to see what does and doesn't sell and maybe even find your own things you prefer to gather as well.
You can do all this while waiting for your leves to build back up. Using leves while gathering your own mats for the items will actually make it so you lose nothing leveling them and maybe even make some money. Mastercrafts are a whole nother beast, but I'd hold off on those til you're fully prepared with all 50 crafts or it WILL break your bank. GL.
