Ldk Unfortunately it doesn't seem that there is a way to use the Sprites of one layer to mask an other layer in the way that you want. I raise (again, I know, I must be very predictable by now, I am sorry) the need for a masking system in Construct 2. Blending modes just doesn't cut it.
What you can do however, is to use sprites as color transparencies on top of your art sprites within the same layer(s). Set the webGL effect to to overlay (or color) and make sure the layer(s) "Force own texture" parameter is set to "No".
Here is an example capx, using 2 colored "transparencies" to simulate the warm color of the sunset and the blue color of the night.