yes please I'm also looking for this feature. At the moment I work on projects templates that have dozens of assets to a page and I have set up layout guides for these where needed. Problem is when the guide colour then blends in or matches the colours in the artwork I want to be able to do a global change of all layout guide colours to be a contrasting colour to the artwork. I would have thought you could set up a variable for this or even swap and replace the hex value but it doesn’t seem to work no matter what I try. I'm having to go in and change them one at at time. it would be great if this could please be addressed