The visible grid is a document property and its cell spacing is uniform for all views/CPlanes. As it is measurement based and not view based, different zoom levels will make the view have larger or smaller squares as seen on screen. There is no workaround for this that I know.
For each display mode, you can vary the grid properties and extents, but not the cell size as far as I know.
One idea that might work is to hide the grid and use an image of the grid as Wallpaper - which does not change size as you zoom. Will take some fiddling with the image size though to get it to be just the size you need.
Hi,
V5
Diego Krause…that did it, zoom and all three grids same cell size and scale same time.
Fred_C thanks, …well thats odd as that link says it does same as the linked viewports, but I ran it before Diego’s and nothing happened.