Here is a script that should set all selected objects’ display mode in all viewports at once. Choose the desired display mode from a list box. The companion script is for removing the display mode.
SetObjDisplayModeAllViewports.py (1.8 KB)
RemObjDisplayModeAllViewports.py (775 Bytes)
Applied object display modes should be transmitted by Copy/Paste between instances as well as export/import (.3dm from/to Rhino, not other programs). This works in V5 here in some brief tests. SetObjectDisplayMode is still viewport-dependent, so if you have different viewports set up in two instances of Rhino, it may not work when copying/pasting between.