If your model is entirely white, the egg loader will avoid creating a color column for your vertices. So the easy answer is: make sure your vertex color is always white.
Note that you probably won’t be saving gobs of memory this way, since the color column is only four bytes per vertex.
I already was aware of the low memory impact but we’re targeting really low spec machines.
Well, and after developing for the PS2 for a few years, I guess I save memory by habit…