If you needed dias to complete the calendar, then you simply did a poor job in utilizing your tools, and also probably didn't take full advantage of the daily challenge option...
Again, my tiny pathetic FtP HMA cities easily cleared the calendar and had 5 and 3 'extra' gems they picked up on the final day. (which turned out to reward 10 scrolls each as the calendar had been fully collected, so nice surprise there!)
My main city on N-world:
0 dias spent.
13 grand prizes (264 idols collected)
calendar completed
32 tablets completed (no gold tablet sadly.
)
My dia farm on J-world:
0 dias psent.
11 grand prizes (227 idols collected)
calendar completed
2 tablets completed (don't care about spending extra time on this world
)
Success or failure in this event (and the past couple Halloween events) depends entirely on how well you maximise your tool usage.
Dynamite is my personal favourite, since it's great for effectively sneaking around those annoying brick walls and otherwise opening a path that would otherwise have eaten up 2-4+ other tools!
Sure I never typically get more than 3-4 blocks removed with it, but it's real value for me is how it gives multiple options to use the other tools more effectively.