All the painting was done without any projection, all done with multiple layers process on susbtance painter. For the cloth I try to figure where the sun hit, which part are more expose, which part are more use…etc
For the skin I just apply a first color depending of the skin you want and add the variance colors of the skin (red, blue, green, white, black, orange …etc) with consideration where the skin have more veins, bones, grease…etc and play with mask, brush and opacity.
This is the same process of Glauco Longhi, he tell how he do at 30 min of the video : https://youtu.be/C7XsmpKvVRA?t=30m3s
I hope that’s help you