lots of interesting things there
I totally agree about the importance of using reasonably good paper - it just behaves so
I had this problem with one class of students - they'd bought watercolour pads from a well know cheap cheap chain of bookstores/art materials shops. The paper was like blotting paper and one lady was despairing of ever learning to use watercolours. I got her to work on the back of an unsuccessful experiment of mine and she was amazed to find that she was actually doing pretty well
she'd just never get anything good on the awful blotting paper she'd been insisting on. She changed to 'proper' paper and did some really good work and the class gradually changed over too.