Bit of practice with varying multi-reference use, about 45 min. each.
#1: Starting, no focus, muddling all referencing, not paying attention.
#2: narrowing down, more focus, better use of multiple references (ended up taking some visual cues for the face from model Alice Vink)
#3: No reference (except #2 in corner), and going by memory of what I just focused
(I tried to make #3 a bit of a Rarity, a better attempt than my previous: Rare Practice)