I think the simple answer to your questions would 1.) yes, use the CSI lines. 2.) Add line weight as you go during the sketch phase and later on too. I am going to give you a much longer answer now. I think the point of the Master Line study project is to see how the artist you are studying used their lines throughout the entire composition, n a specific or concentrated area, or both. Keep in mind, the artist who produced a particular piece may have a different process to complete their work than another artist may have. Someone like Peter Han or Karl Kopinski may not need to go through a sketch phase because they have tons of experience, techniques, problem solving skills, intuitive understanding, and other skills that enable them to do so. In fact, Proko has a great video on YouTube with Peter Han on building your ability to draw from imagination. I suggest you watch it because it gives great insight into the sort of skills someone like the possesses. The reason I bring that up is because they may have a more intuitive control of line weight than a beginner or intermediate students, or even professionals, might have. Ultimately, in this project, I think you want to pay attention to these things: 1.) How the negative space is used 2.) The flow and energy of the lines 3.) The line tapering 4.) All the various line qualities they may possess and how the artist uses them, blends them together, or chooses to use them in a composition (remember, that's the thin to thick, hard to soft, etc. stuff) 5.) How much detail is used in specific areas (Stuff farther from the camera "could" use lighter line weight or have less detail) 6.) How cross-hatching or lines may follow the form I could go on, but I think you might get the general idea. The important part is that you aren't just mindlessly trying to draw each line and instead trying to see the effect each line brings together. The other half of this is you asking yourself why an artist might choose to make a line the way it is. For example, a thick and dark line might help separate one part of something's form for another, or indicate it is holding a lot of weight. So, I think that is more in the ballpark of what you should try to accomplish when doing the master line studies. I still think that means you should draw the piece of work you are studying, but you should try to remain goal oriented and mindful of the reasoning behind their decision that you can make out and what effect the lines produce. Lastly, I would recommend starting by sketching the big shapes, then go in and do the medium shapes, and the the small shapes so you can get your proportions right ahead of time. I hope this helps. Good luck, and keep at it. You too can become as good as the great masters :)