The Perfect Cover function creates guides. I like to add a guide down the exact center of each of the three panels, back, spine and front. This helps in centering objects or moving text on the spine so that he x height of the text was along the centerline. To do that I need to know where the existing guides are. The rulers along the top and left side are not fine-grained enough.
I can double click on a guide and get its location via the Guide line dialog. But it is all too easy to move the guide or even snap it to a nearby guide instead.
Two features would help me out. If I could freeze guides in place temporarily that would help me access the guide location without moving it. Alternatively if there were a window where all the guides are listed by location, similar to what Scribus uses, then I could calculate and add the center line guides there instead.
Currently my only safe path is to snap a vertical line to the guides in a temporary layer so that if the guide moves I can snap it back to the vertical line. Or I can undo the unwanted move if I catch it in time.
Any other suggestions?