Hi there!
What an intriguing job! I just can't wait to see your picture to be sketched/copied.
Do I understand correctly that it is the hight of the textural paper to be used is 1.2 m, not the width? I know excellent French paper with density of 300 gr/sq.m, made of 100% cotton. It is designed for multiple layer watercolor.
Are you interested more in multiple layer technique or in 'a la prima'? I like both very much, be it the pastosity and the intensiveness of layered watercolors, as if we used oil, or the airy playfulness of 'a la prima'.
It would be pleasure to discuss the above with you.
Regards,
Elena