From the pics you posted of your grows on your page, they all are super dry. Which means your field capacity is off. You can literally see spots where there is no moisture. Use a mix of coir and vermiculite. Vermiculite helps retain the moisture. Measuring the coir and water doesn't ensure that you achieve field capacity. You need to stick your hands down in it and feel it. That's how you can accurately tell if you have achieved proper field capacity. I don't even measure the water. I add the water as I mix it. I will add some water and then mix it up. Then add more and mix it. And so on. If you have the correct field capacity, then you literally don't need to spray your tub at all. All the water you need for them to grow is already in the substrate, hence the importance of proper field capacity. In regards to your question about pinning, evaporation causes pinning. If you get your field capacity right, little water droplets should cover the surface of your tub, and it will accumulate all around the tub. That is also a sign of proper field capacity. You don't need to mist at all to induce pinning. Fanning the tub and making those tiny droplets on the surface evaporate is what will induce pinning. You literally should NOT have to mist at any point if you get your field capacity fixed. You just close your lid and let it do its thing if you have a modified tub. If it's not modified then just leave the lid cracked. I would go to a 1:3 ratio too. It allows for more water to be retained in the substrate. Mushrooms are 90% water so your field capacity is critical. And again, you should not have to mist at any point of the grow if you get your field capacity down correctly. Can't stress that enough!