For me, right after opening Moon Shop and having Cave Keys available, get Cave Keys and only Cave Keys .. Medium Threads/Medium Refines drops everywhere and it is available for redeem in Monthly Event .. For Sun Scrolls, always Advance Refines or Charms, you c*so opt to get some some Bond Element Scrolls but in my opinion, its only needed to get if you are planning to have Minato Jonin's bond skill or someone ..