I never pour more than 1/8" at a time. Sometimes less. Usually the less. More than 1/8" and it will crack as it dries. Setting time varies with the amount of humidity in the air. Then the pour is ruined and will have to be removed. The cracks will never fill after that. It pours white, but as it dries it goes clear. When completely dried, it is totally clear. Then the next pour can be done.
The pour for the backwater above, was a total of 5 pours. I would pour and just leave it to work on something else. It's not an overnighter. It took four days to do the five pours. It is something you do not want to rush.
The amount of layers is actually, up to the individual. I have used it for small back water or streams only. As it dries clear, you can give it the appearance of depth with color or shading the base or bed before the pour. Also, as the color is added to the gel, you can make it muddy, clear mountain stream/no color, etc...I also notice I forgot to add the word Medium to the product description. So it's: Self-leveling clear gel Medium. It comes in different viscosities. The medium, from my point of view, is the best for doing this work.
The effect is really nice! Yes, it isn't an instant thing, but I have found that anything in this regard, slow is good!
One more note here: This product is used by artists, to give their paintings a lot of texture.
Sure wish I could find that file!
Dave