Lots of questions in your post. Here is how I study. I work full time so I usually practice drawing for one to three hours a night depending on how tired I am. I always make it a point to sketch something for at least an hour every night. The evenings are for practicing and watching tutorials. On the weekends and days off, I’ll spend about 6 hours drawing a day. On these days I spend about an hour practicing and five hours working on a long drawing. My long drawings can take me 8 to 12 hours to complete depending on the subject matter. These drawings go into my portfolio.
I use sketch, drawing and toned paper as well as Bristol and watercolor paper. I use all sizes of paper starting at 9 by 12 inches to 18 by 24 inches. I chose the paper size based on my subject matter. The size paper I like best is 11 by 14.
Regarding sketch books, I have a lot of them. I usually carry a small 5 by 7 sketchbook with me all the time. When I take breaks at work, I go outside and sketch a tree or a car for 20mins. I’m usually standing when I’m drawing a tree, so I hold my sketchbook at a slant when drawing. By the way this is a hardcover sketchbook. A spiral sketchbook doesn’t work very well when you are drawing outside. The sketchbook I use at home are big and cheap. I like 14 by 17 size sketch because it gives me a lot of room to draw my ideas. I have a desk top easel that I put on my kitchen table when I’m done with my evening meal. The easel has a 30% slant that works perfectly for me and my sketchbooks. To bad you can’t use a table easel, it makes my sketch life very easy.