I click Update Layout, then Save after adjusting measure widths.

Seems to work.

By your word “measures” you mean measures (in “Finale-speak”), not staves, right?

If I understand you correctly, you want the measures to be wider, right?

The measure widths are a consequence of the Music Spacing settings.

Go to

Document menu > Document Options > Music Spacing > Spacing Widths

I suggest that you try a bigger value for the Reference Width.

Try e. g. 36pt.

All measures or only some measures?

If measures are too wide, the eye has trouble seeing everything and getting on to the next measure, IME.