Tidal Wave - First kinda-successful grow. Why did it only pin on the sides?

[u/un_veiled]

First grow that actually produced something. I've done a fair amount of reading, but I'd like some real-world input before flush 2.
Everything pinned off the sides where the block touched the bag. The top just grew a thick white crust and did nothing.
From what I've read, the top looks like overlay. My guess is it dried out or got too much air, while the sides stayed humid against the bag and got light through the plastic. I also think I flipped to fruiting too early, before it was fully colonized.
First flush was [129 g wet / 13g dry]. Some decent-sized ones in there.

What I did after the flush:
Picked everything, including the little side pins
Scraped off stumps and dead bits, and lightly forked the top in both directions to break up the overlay
Cold soaked it upside down in the fridge for 12 hours. I went cold so it was safe to leave overnight, and pulled it in the morning. Most of what I've read says 12–24 hours, and this is a dense block, so I'm wondering if I should've gone longer.
Drained it on a rack until the surface was matte, then leveled it since it was lopsided
Put about 1 cm of North Spore coir on top, sides bare
Back in an automated tub: humidity high, fan low and pointed up, lights off until the mycelium pushes through the coir, then switching to normal fruiting conditions

Questions:
Is it overlay, and did fruiting too early cause it?
Was 12 hours enough for a block this dense, or should I go 18–24?
Will the fork plus casing fix the top?
How do you prevent overlay in an automated bin? Fan settings, humidity, misting the top?
How do you tell when it's actually ready for fruiting?
Anything you'd do differently?

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[u/herbal_coma]

Anytime I harvest and gear for the next flush, I use cold water and dunk it submerged for about 10-12 hours. You don’t need more than this, especially if you’re only to your second flush. I take my block out and put it STRAIGHT back to fruiting conditions and have pins again within two days. I also don’t use a casing layer, I don’t think it’s necessary but I also have never had overlay. But you answered your own question with exactly that. The overlay has caused your block to not be able to fruit on top. If you put it into a monotub- you can at least have EVERY side growing.. not sure your exact set up, but this is how I have mine. I can’t speak to the overlay- I have never dealt with it but I’ve heard people do fork that. So I wish you the best of luck mate! If I were you, I’d have another block or grain bag/jar colonizing just in case this cake doesn’t meet your standards. Mush love, and happy growing mate! 🍄‍🟫

[u/un_veiled → u/herbal_coma]

There was no casing on the first one and I felt the cake getting too dried out out on the sides so thought it might help the top pin? Idk complete rookie lol

[u/un_veiled → u/herbal_coma]

And I have two tubs I’m filling up this weekend lol - this was just a little shot in the dark of a aio bag I bought