I actually created a similar theory to the one you just proposed a while back
I think the 10% is whatever you think it is--science, or just rational, or integrative. We know how interlinked and intertwined all of our four main systems are: senses, emotions, reason, intution. When all are in tune to perfection, I would say that that 10% would shoot up way high.
In order to increase our intelligence with brain gym, for instance, we touch our elbows to our knees... right. 
Or in order to free up the inner mind, we release emotional trauma. Emotional trauma and touching your knees are seemingly unrelated to intelligence... but it's all connected. There's always a danger of being too reductionist/ too cause-effect. Synchronicity/ I Ching is much better way.
In Anna Wise's book The Awakened Mind, she measures the brainwaves of an Enlightened Zen Master... wow. Then she measures them as he meditates... double wow. You should see it, there are no bottle necks... just amazing. I think that's pretty damn near 100%. It's called 'The Evolved Mind' brainwave profile, and it makes my mouth water!
Fascinating, where do enlightened people go when the meditate? What do they experience? Their waking/normal state can already be said to be the deepest of meditations. Fascinating.
