It looks like you're doing a great job with your pp'ing. I had a really hard time figuring it out on my own. Taking a class at my LQS was the only way I finally 'got it'.
I use regular copy paper all the time with no issues. I couldn't even tell you what size needle I'm using but probably a 12 or 14. When I took the class, the instructor made zero mention of type of paper or needle size. I used primarily batiks for my project for that class - and selected the fabrics with the aid of the instructor, so if the batik/paper/needle size was to be an issue - she certainly never mentioned it.
Enjoy your class.