I've just recently done this part of crafting myself (currently 35 crafting). From 20 up to 33, I went to Mahagra and dug up as much slate as I could, turned it into bricks which I left on my disc, then when that was full, make and deconstruct Slate Strength Chest Scales. You can get a Slate Cargo Disc (2000 bulk i think) at lvl 25 crafting, or a Tarbash's Sandstone (6000 bulk but only one item, i.e. slate bricks) to help you out with this. From 33 I've moved to Iron Dexterity Chest scales (don't have the strength form for this) and will probably keep making these til 40.

And yeah, I'd wait til you're adult to LS, I just turned adult a couple days ago and its far far easier, plus if you're up to 50 craft you'll be able to carry more. I found being adult helps on t1 stuff the most when you have to make crystals... those are a real pain because the only crystal shaper on unity is a good 5 minute walk round a mountain, as an adult you can go up and over within a minute Not only that, but if your craft is higher than the materials you need, you'll be more efficient (e.g. for half the t1 materials at the moment, I'm on 2:1 efficiency because I have the III Mastery for all gathering/crafting).

Hope this helps a bit