Updated data points in case anyone is interested. Overall, it looks like I should be good to go with getting the final hat to max evolve before the event is over. I don't think I've been particularly "lucky" in any way -- I'm experiencing plenty of empty screens just like others -- but it does seem 100% essential to really maximize your available resources. To me, this means some basic rules:
1) Never use a light source on foggy areas that are empty (i.e., no prizes) unless it's a candle being used to progress forward on the map.
2) Only use lanterns when there are at least 3 "valuable squares" to illuminate. I define "valuable squares" as any squares that either A) are foggy and have a prize in them, or B) are shadowed with no blockages -- i.e., no foggy/empty squares, and no shadowed squares that visibly contain a barrier.
3) Only use flash bangs when there are at least 4 valuable squares to illuminate. To be fair, I used lots of flash bangs when there were only 3 valuable squares, especially when I ran out of lanterns -- but I think the target here should be 4.
4) Only use candles to either A) Progress forward in the map, or B) remove the fog from a prize-holding square. If you use a candle to illuminate a shadowed square on the top/bottom/back of the map -- i.e., a square that will not directly assist your movement forward -- you've made a mistake.
5) Constantly be progressing forward. You do not need to clear whole screens; in fact, doing so is likely wasteful. There is no "end" to the map, so maximizing the number of squares you illuminate over the total course of the event is more important than illuminating all of the squares you come across. When you try to clear whole screens, you'll invariably end up breaking rules 2 through 4.
Not super useful right now (since the event is almost over) but may be useful if this becomes a standard event format in the future.
Event Statistics To-Date
Total Mats Earned:
67 quests completed: 3,806 mats
13 daily rewards: 13*45 = 585 mats
Quest Reward: 300 mats
City collections: ~350 mats (estimated made based on: (known mats earned - known mats spent) - current mats held)
Total mats earned: 5,041
Mats Spent/Purchases Made:
Total Mats Spent: 5040
Total Purchases: 12 big packs
Event Performance:
Big Packs Purchased: 12
Grand Prizes Won: 11
Total Cats Found: 220
Cats Found Per Big Pack Purchased: 18.3
Future Estimates (over the remaining time of the event)
Remaining Mats Available:
8 Quests: 595 mats
8 daily rewards: 8*45 = 360 mats
City collections: ~215 (estimated based on previous 350 mats/13 days, for the remaining 8 days)
Total Mats To Be Earned: 1,170
Current Mats Held: 1
Total Mats to Spend: 1,171
Event Performance (remaining):
Big Packs Purchases: (1,171 / 420) = 2.8 big pack purchases left
Expected Cats: 2.8 big packs * 18.3 cats per big pack = 51.3 cats
51.3 cats + 0 current cats = 51.3 cats = 2.57 grand prizes = 1 more hat.
Based on these numbers, I should be able to get the final hat required to max the Witch’s Hut. Obviously there’s some fractional issues in here – I can’t buy 2.8 big packs, for instance – but even if I’m only able to buy 2, that would leave me 4 cats away (based on my average cats per big pack) from the last hat I need, and I’d have 331 event mats to buy the middle pack/individual items to get those 4 cats. I’m confident it will happen.