I was able to conclude the 'dreadful' Chapter 7 last night but was over-due 36hrs.. playing full time all day with 6hrs sleep.
Once reaching Chapter 8 (for my game.. and not before) it's true that the OYNX CRYSTALS and OYNX PEARLS drop rates change and are more abundant.. but I was not able to finish Chapter 8 yet, as I started with 0 Oynx Crystals.. and the 'real' collection of the Oynx Crystals has just started but being every 4hrs takes alittle time to accumulate.
Chapter 9 will be started late, with less hours over-due, but at least acceptable, for my style of play. I never depend on the last minutes of the timer.. and suggest players who are participating in the event not to do so! There isTOO much work, sacrifice and passion to throw away for an around-the-world timer, burping game or wifi black-outs.. including S8 black-outs that have happened in the past, unfortunately.
Suggestions are:
... Keep doing the Adventures continuosly... speed up toward the end if you can so as to do more Adventures per day as this is where the Oynx Pearls come from. More Pearls you collect.. more guarantee you have to be able to finish on time without stalls.
... Prepare ALL materials needed during your stall-time so you can fly through the Chapter after. Keep your Potion Shops, Work Shops busy all the time.
... Keep collecting materials used for the Adventures!!!
... Keep up you stock of Jewels, Wood, Stone, Well collections.
... for those who have goal black-out problems, first check your inventory of materials used for that goal, if you're maxed on something, use, sell or somehow throw away.. this has resolved problems for me.
And yes! this is a tricky event with a terrible stall, but hoping after Chapter 8 the road should smooth out. Patience with high hopes are the best tools to use.
Good Luck to all and hope you find LOTS of Onyx Pearls!