How did the work of Chuck Close's grid in his work change over time?

I've watched an hour long documentary in my Art History
class this semester about Chuck Close. Before the spinal injury, Chuck Close was a
remarkable painter, being able to paint grandiose photo-realistic paintings of people
depicting different facial expressions. Fast forward a bit with the spinal injury, Chuck
Close has to deal with his lack of muscle control. However, that didn't stop him from
painting on large canvases. He has to have a team of assistants to draw out his pictures
for him on a grid and transfer them onto the canvas and then with his paintbrush, begins
a meticulous journey using his own color theory, to paint realistic portraits of
himself. Although, it seems that he has been restricted from doing photo-realism, his
work with grids, have helped him to learn more about colors and develop his own unique
form of technique to deal with his muscle loss.