I prefer option B for notes and cues, but I have also seen people make rather larger margins around a script with construction paper or the like and you can make notes that way and save paper.
If taht makes sense
I prefer myscripts to be two sided (in a 3 ring binder) so there are fewer pages to flip. I usualy dont enlarge the orignal when i photocopy it into the binder, so there is still about 1/2 of each page white for writing notes arround the edges.
I like the scripts done so its just one sided (making it 2 sided is too complicated for me! haha) plus then my friends and I have plenty of room for hang man and drawing when we are bored (that doesnt happen often) and when I lose a page I only lose one page instead of 2! (yes I keep them in a binder but they are always ripped out!)
Normally when I deal with scripts as a designer, I just copy them two-sided, as I don't need to waste paper and prefer a smaller notebook. When I do prompt books as a SM however, what I normally do is a trick I picked up at one point or another. You need to be right-handed for this to work though:
1. Photocopy the script onto three-hole punched paper, single sided, with one trick:
2. Before you actually do the copying, turn the paper around so the holes are on the "wrong" side.
It takes a little bit of experimentation to get it to work right.
Once you've done this, you put the script in backwards in the binder. What you end up with the script pages on the left side of the binder, and a blank surface for notes and cues on the right. That way, you can make notes without having to cross your right hand (your writing hand) over the script page, so you can follow the script and write at the same time.
Another thing I like to do is (especially for larger/more complex shows) to make two copies of the script. I put one in my prompt book and use it for blocking, props, and other notes. The other one I keep in the drawer until tech (so I can resist the urge to write on it too) and use that for only the actual cues I will call during the show. That way, I don't have to look at all the blocking and notes when I'm trying to call the show. The only notes I have in front of me are the actual cues I need to focus on.