I'm posting what I found out when upgrading my heart and soul through the event and how much currency you'll need per stage.
Heart:
Hongmoon Heart stage 5-awakened stage 1: 3 stones
Hongmoon awakened stage 1-> awakened stage 2: 3 stones
Hongmoon awakened stage 2-> awakened stage 3: 3 stones
Hongmoon awakened stage 3-> awakened stage 4: 3 stones
Hongmoon awakened stage 4-> awakened stage 5: 3 stones
Hongmoon awakened stage 5-> true hongmoon heart: 13 stones
true hongmoon-> virtuous 1: 7 stones
virtuous 1-> virtuous 2: 7 stones
virtuous 2-> virtuous 3: 7 stones
virtuous 3-> virtuous 4: 7 stones
virtuous 4-> virtuous 5: 7 stones
Total stones for heart: 63 stones
Soul:
hongmoon soul 1 -> hongmoon 2: 3 stones
hongmoon soul 2 -> hongmoon 3: 3 stones
hongmoon soul 3 -> hongmoon 4: 3 stones
hongmoon soul 4 -> hongmoon 5: 3 stones
hongmoon soul 5 -> awakened ascending : 6 stones
awakened ascending -> true ascending: 12 stones
true ascending -> cosmic 1: 3 stones
cosmic 1 -> cosmic 2: 3 stones
cosmic 2 -> cosmic 3: 3 stones
cosmic 3 -> cosmic 4: 3 stones
cosmic 4 -> cosmic 5: 3 stones
cosmic 5-> awakened cosmic 1: 5 stones
awakened cosmic 1 -> awakened cosmic 2: 5 stones
awakened cosmic 2 -> awakened cosmic 3: 8 stones
awakened cosmic 3 -> awakened cosmic 4: 9 stones
awakened cosmic 4 -> awakened cosmic 5: 13 stones
awakened cosmic 5 -> true cosmic: 22 stones
Total stones for soul: 120
Rough calculations with the event for me saw ~50 stones total if all currency is only spent on stones and no resets are used. Good luck upgrading.
Let me know if I messed up with my math or stones amounts anywhere.