How to use GPU memory during scrolling?

I'm rendering the content of some PNG's via a 4096 by 4096 RenderTexture, to cram all of it in the GPU memory, for scrolling usage. As each column should be 1024 pixels wide I can store a maximum of 16384 pixels of height to scroll through. I use 4096 as width and height because of http://webglstats.com/webgl/parameter/MAX_TEXTURE_SIZE

But what to do if I want more than 16384 pixels to scroll through in one go?

Suddenly realised:
Should I just use some extra texture(s) of 4096 by 4096? It looks like a maximum of 8 textures is a safe bet: http://webglstats.com/webgl/parameter/MAX_TEXTURE_IMAGE_UNITS

Or is there a better approach?