As I see your attached graphic:

Take a good look at the end of the last measure (= the measure without a clef change).

You might say that the Spacing After Music (= the spacing after the right side of the ‘g’) is too wide.

In the previous measures (= the measures ending with a clef change) there is the same spacing after the right side of the last quarter.

The spacing may look bigger, but that is an optical illusion due to the fact that the stem is on the left side of the notehead.

Unfortunately, Finale does not (yet) provide “optical illusion spacing” according to, whether the stem is on the left side (or the right side) of the notehead.

For years, users have requested automatical “optical illusion spacing”.

Perhaps some day …

My only suggestion:

Try setting the Spacing After Music to a negative value.

Unless this is a clef-reading exercise, I am surprised the entire passage is not written in treble clef.

But, of course, that is a decision for the composer/engraver.

I do not see a difference in the spacing between the two treble clefs; both seem to have the same space between the clef and the quarter note that preceeds each.

Thank you both for your very useful replies.

I have made the whole passage in the treble clef now, yes - it's much better.

But in many other situations with a real need for clef changes, the same problem persists of course. Adrian, the space is the same before both treble clefs, yes, but it is "too big", for reasons that Peter explained so well.

I usually have the Music Spacing widths set to a very low scaling factor (1.1-1.3) to avoid empty spaces - such a shame to have some notes crammed in and others not at all ........

Many thanks again !