[Coco] os-9 default colour scheme

[CoCoList for Color Computer Enthusiasts]

On my monitor, the default green background with black text looks
terrible.  Is there a better combination?  Maybe black on white?  How do I
change that?  It is os-9 level 2.  A pointer to appropriate documentation
would also be appreciated.  I have the level 1 docs but not level 2

Thanks,

Keith