As far as banking any master writs you can't do yet, I really wish identical master writs would stack, the way crafting surveys do, and the way everybody (except ZOS) wants treasure maps to do. As it stands, master writs and treasure maps have a way of gobbling up inventory slots, bank slots, and storage chest slots. It's kind of annoying to click on a master writ to see what it is, and notice that the little sack icon in the upper corner of the popup window says that I have 2, 3, 4, or more of a particular master writ. Wait, you can recognize that I've got more of this same exact master writ, but you can't stack them together for me? Aaargh!
If you have the gold, use that master writ as an opportunity to purchase the motif page needed to craft it, assuming you have the research done. That’ll help you keep on track with learning the styles.
If you don’t have the research you can keep it until you do, as long as it’s unopened. Just keep that research going as fast as possible by investing skill points so you can do 3 items at once.
I do actually go out and do the master writs at the regular crafting sites, unless it’s in IC, and then I visit the guy in my guild that has every attunable station at his house.
They pile up quite a bit (and soak up bag/bank space) while waiting to build those.
I REALLY want a Militant Ordinator Shield motif now, but I hate PvP and its cost is well outside my range, as just one example that has been waiting quite a while.
You can find Militant Ordinator motif pages at guild traders. I just finished off my set with a combination of gold-purchased pages and some bought with AP. The gold prices are typically 50k or 100k. I think it’s a 5:1 ratio AP to gold.
Cheaper than I thought, but still outside my budget. I will look again, but I recall them being more expensive than that on the PS4.