Spacing between trailing grace notes and next note

If you simply trying to get it to look better, then there is a spacing difference between using Grace note after (after the C) and Grace note before (before the G#):

I agree that it is really difficult to adjust the spacing around the G# when using "Grace note after".

[EDIT] It's 6/8 not 3/4, but I was half asleep! I hope you will forgive my mistake?

I think this is one of the weaknesses of MuseScore software.
The software evaluates the Gracenotes with normal note settings and only changes the percentage size so that the values ​​of all regular-note settings are also reduced by the same percentage for Grace-Notes.
(Maybe one or two additional settings embedded in the software are also made.)
To test this: Enter the Style option from the Format menu. Click on the "Measure" title. Change the "Minimum Note Distance" setting and see how grace-notes change accordingly. // Note: if you click the button next to the value, you will revert to the original value (0.20).

Maybe there is a setting or a definition somewhere we can't see (for example in some definition files or style files) and maybe somehow it can be tweaked but I'm not sure about that.

If this style window had a setting like Gracenotes-note-distance, it would be easy to use, for example.

So it required some fiddling, but here's how I did it...

Step 1 - Select the g sharp and increase leading space in the inspector. The g# moves right, but so does the grace notes.

Step 2 - Shift-select all the grace notes. This will select also the C-note, so choose "Grace Notes" in the inspector to select only the grace notes. Now, adjust the X-offset under the chord-section in the inspector to move the grace notes back to the C-note. But hang on, now the C-note moved away from the barline!

Step 3 - Select the C-note and adjust its leading space in the inspector to move it back to the barline.

And success!