Using two fullscreen Graphics.DrawTexture images, overlapping?

I am using two textures, one for terrain, one for the sky, and I want the sky behind the terrain… and I googled this pretty hard before coming here, but I am finding little help in this department…

I tried having a regular unity standard skybox, but the graphics.drawtexture for the terrain seems to not show the skybox behind it (even though some pixels are 0 alpha…it is just black on those pixels? that bugged me, but ultimately I want two “pixelated” textures rather than a whole skybox, so dont worry about that)

I also tried two cameras, main with its script drawing “terrain” with transparent upper half, secondary with its script drawing “sky” texture2d, but changing depth makes no difference… the sky texture seems to always appear on top regardless of which had higher depth.

Is it possible to draw two seperate graphics.drawtexture’s with one of them “on top of” the other graphics.drawtexture?

if not, I suppose it would be possible to combine the images, but would have to be constantly updated with terrain being broken up, so a comparison of two pixels arrays which then combine, after iterating through every pixel, every frame… it just sounds like bad news… two seperate textures are sorta what I require…

I would just create two camera-aligned quads with different textures.