Hi Linda,
so far, there are no large paintings displayed in my website. However, I am working on some experiments, religious groups of life-size figures (that's about 2,5 x 3 meters or so), and I also have a project to make a series of 12 landscape paintings of areas that surround my city (their size will be at least 100cm x 150cm). But, yes, I try to avoid lead white even for my regular 70cm x 50cm head'n shoulders. To be sincere, as a self thought artist, maybe it's too late for me to worry about this. When I was a teen, I used my fingers (or even hands) to cover large areas of the canvas and gain time. Brazilian brands never showed any specific interest on warning about hazardous pigments. All labels showed the same "toxic, keep away from children bla bla" thing, which you can read here in almost any product that will not feed you if you swallow it. How could I be aware of heavy metals and it's accumulative danger? Only few years ago, when I went back to my easel after a loooong break and started learning about pigments, I could understand how harmful they can be.
Maybe it's really time for a blood test
Ant