Thanks Tito for your input and Bill for your mini demonstration
I used to tone my canvas with paint thinned with turpentine and without any medium. But I will go and try the way that has been suggested by Bill now.
I never used acrylic for underpainting. It is just a matter of individual preference in my case. I love the consistency and texture of oils, but not so much with acrylics myself.
Thanks again!
Mai