This indoor, ambient window light session netted 157 images. Of these images, 10 were 2/3 body portraits, 82 included head and shoulders (or were framed slightly wider) and 64 were headshots with a significant number of those being close to minimum focus distance. All images were captured at f/1.2 for the shallowest, most-AF-challenging depth of field possible and eye detection AF was exclusively in use.
Of the 157 images, ten were focused on eyelashes (usually acceptable, mostly close to the iris), two were focused a similarly-short distance behind the iris and only two images misfocused beyond iris-to-eyelash distance. The other 143 were optimally focused on the iris.
That the camera was being handheld with me in a somewhat squatted position and the subject standing (sometimes leaning against a wall) meant that our movement could easily have caused any of the less-than-perfect results.
I remain very pleased with the EOS R's portrait AF capabilities and the RF 50mm f/1.2L is a very impressive lens, perfect for portraits.