The contents were still quite hot in the middle 6 hours later. I turned the tub on its side on an angle and left the water to drain for 5 or so hours. It was barely dripping by then.

I mixed the contents and then transferred it to a bigger 100L/25gal tub. I put a layer of the medium on the bottom & sprinkled a good layer of inoculated grain spawn on top. I ended up with 5 layers of medium & 4 layers of grain spawn by the end. Everything was moist but not dripping, probably just a tad too moist of anything.

I don't love the firebricks I used which look like they contain recycled softwood (probably pallets) & cardboard. I'll probably just burn them for heat if this doesn't work out.

Now I need to wait 2-3 weeks for the tub to colonize & for me to figure out what I'll do with it (if it doesn't get covered in mould). If the whole tub gets a nice white covering of mycelium, I'll probably end up fruiting directly in the tub to see what these things look & taste like.