In my case, a further complication as I moved to watercolours at that stage, and the two models had very different skin tones.
This is the one I'm happiest with - We did a ten-minute drawing, then we had a break, and after the break we have the choice of continuing with the same pose for 15 minutes. I use that time to paint.
While my paint was drying, I sketched with a Sailor Fude in one of my sketchbooks. This was probably 10/15 minutes. Lots of mistakes and distortions. Plus it was hard to sketch while standing with my sketchbook on my arm.
I brought two watercolour blocks, so for the last pose (10 or 15 minutes?), I went straight to watercolour. That paper is rough watercolour paper, so the paint can skip, like it did on the left arm of the girl on the left. I think I should stick to cold pressed paper for this.
They look like they're sitting on the beach.