Change width/length of last system? Measure adjustments?

Day three with Dorico… still learning! :laughing:

I have a finished piece, and have adjusted the size of the systems and their margins to my liking. I would like to address the final system. The default arrangement leaves the final system approx 1/2 the width of other systems… despite having a greater number of measures! A bit cluttered IMO. (see pic)
I can’t seem to find the options to change the width of this final system… nor any manual measure width adjustments. Please help a newbie! Thx!

Fantastic! Glad you could find it… 20 minutes of searching this forum with several keywords… nothing for me!