Hi Dr. Dave:
I’m working on a client site and just went through something similar.
1. In Appearance>>Parabola Settings>>Header Settings.
There, adjust header height from 120 to something smaller or larger. Adjust Header Content Spacing, which is basically the margins for the logo image. SAVE
2. In your graphics program resize the header image to your new larger size and upload it. SAVE
Make any further adjustments as needed. Remember to save!
Good luck!