I am with many who have already replied to this but in short: I am flexible with the needs and resources of the show. I don't always have the opportunity to make a separate script for calling cues.
I am right handed, so my script pages are on the left, my blocking pages are on the right.
If I am using this same script for calling, I will reverse the pages at that point (yep, hole punched on both sides!) so that my calling script pages are on the right side. I do this so I can easily reference and/or make blocking adjustments if anything changes during tech without referencing another book.
I do, however, like the clean look and feel of a separate script, but I also like having all the information in front of me at one time. (Alternatively, if I have both scripts separate - blocking and calling, I still keep them in the same binder if I need to reference both, but don't want 2 books).
Those are my 2 cents!