As I can see, guides can only placed be mouse movements. This is not very precise. A possibility to add or move guides with exact x or y coordinates would be very helpful.
Even the workaround to zoom in and using the rulers for a more precise placement doesnt work. Guides can only added or moved when the zoom factor is 100%.
Guides are very important to give your title a constant visual structure. At this time a correct positioning can only done by checking the x and y coordinates for every relevant object, even if you are using guides.
While we’re at it. Using the snap to guide helps to place your object. But while resizing objects guides seems to make no effect. The moved corner of an object is not snaping to a guide as ich can see it. This behaviour would be nice.
I can adjust guides just fine when zoomed in (see pic), just drag the handle on the left side. But it’be great to be able, say, double click a guide to type in the exact pixel position. Just like in Photoshop. Snapping for resizing is a great idea, too.
o.k. zooming works under the following condition: the scrollbar must be totally left, to move the horizonzal guides and totally top to move the vertical guides. Otherwise every try to move seems to generate a new guide. Perhaps my picture helps to understand.
So you are right, zooming may help to place guides right, but it could work much better.