Yes, you are right to caution people, Boon. Oxides aren't harmless. A spray booth and mask are very good precautions. Glazes are also dangerous to spray, since they contain silicates which can cause irreversible harm to your lungs.
Could you use a sponge instead of a brush? A natural sponge, like a little silk sponge? It might be easier than making up a batch of oxide, ball clay and water that is big enough to dip a big pot in.
Joanie