14 x 11
Maybe I've got a high tolerance for odd, but I still haven't hit the limit. There's pure green in her cheek, and blue in her arm, but I still have an overall belief in the skin as caucasian and not alien.
In her difficult but fascinating book "Vision and Art: the biology of seeing", Margaret Livingstone pointed out that putting colour at the edges of objects can convince viewers' brains that the entire objects are that colour. She used a red roof in a Cezanne painting to show this. Though the roof was mostly ochres and neutrals, the red perimeter of the roof shape influenced the entire interior space and made it look like the whole roof was red. Cezanne used this a lot, and here's an example:
In "Young Model", the warm orange colours in the top surface of her arm function in the same way. Though there are a lot of cool, unnatural colours in the arms, those small, orange marks can override them and give the impression of a peach-coloured arm. It's an amazing phenomenon and it gives an opportunity to explore a great deal of colour without losing the sense of an area.