Generally, after maxing out battle armor and getting to like medium threads, the best option for moon scrolls is to just go for purely cave keys and maybe just have a reserve of 20k or so if you ever need something like chimes, Myoboku gifts, or experimental vials.

Sun scrolls should be used only for advanced refines or charm packs, personally I like the advanced refines but sorta depends on you.

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 ..

You should try go for Cave key when the event have cave key rebate,it gives you gold essence.

Which give you more survivability.

Golden Rope tools(Injury-decrease critical damage/Deal more Crit dmg to player+Critical-Lesser chance of crit by player/Higher chance of crit-ing player).

Cave key would be one of the best choice from moon coin

Of course if you feel you need to upgrade other power-up system such as Ninja card/Myoboku just go for it.

depends on what page in mt myoboku culitvation you are.

first 8 pages of that feature grant a ton of power, so imho, myoboku gifts in that case has not to be undervalued.

well if u like spend only on moyoboku and keys........buying out all moyoboku its easy...its 15 per day=3k moon coins.......rest spend on keys....im buying those for like 3-4 months straight........... page 14...280 moyoboku per upgrade...each upgrade 150- 200bp rise..