Easy to make and handy to have!
https://youtu.be/EdvGwob0LKc
That is great. I do something similar except I use the actual reel that I will be using for the rod, and center the line. I use this technique to also select guide heights so that the line is centered in the guide to allow the greatest casting distance.
I do the same myself 👍
I assume you are talking about something more along these lines: https://youtu.be/pdt5Ft9mM9Y
That is correct.