The super-fine lineweight of V7 is killing my eyes. Is there a way to set it up to be similar to V5?

can you post a screenshot example? generally you can change the line-weight of each display mode.

It’s under Display Options. Here’s how to find it:

This sets curve thickness, but you can set values for other objects in the same menu as well.

Thank you for your help, but this doesn’t appear to be a global setting. It only affects certain selected curves. I’d like it to make all curves easier to see on every Rhino file I open.

Hi -

The setting that was shown in that video is a global setting - for the display mode that is modified and for the object which settings are modified. For different types of objects and other display modes, you would have to make the same modification to the settings.
All that said, I wouldn’t assume that you will be able to get Rhino 7 to display the same as Rhino 5. A lot has changed since then…