I have started my next reproduction while waiting for my Vermeer to dry between layers. I love the detail in this painting and am going to enjoy spending a lot of time on the intricate details. The sfumato style of DaVinci will be a challenge and require a little bit of research.
The reproduction is on a 16" X 20" wood panel which has been primed and sanded several times to ensure a very flat and clean surface. The initial guide lines can still be seen in red. The drawing was done with thinned down umber and a proportional divider. I will be moving to a very detailed grisaille when the umber dries.
My umber sketch: