We encountered a bug in versions 6.4 and 6.4.1 of ShowTime where adjusting the width of your logo in the header settings was having no effect.  We have pushed a fix for this issue in version 6.4.2.  If you have one of these versions and are encountering this issue, please follow these steps to fix it:

Login to your store as an administrator and edit your header.liquid file. To access the file, please follow these steps:

• From your Shopify dashboard, click Online Store > Themes and look for your published ShowTime theme
• Click the Actions button and choose Edit Code from the drop-down menu
• Navigate to the Sections folder and locate the file called header.liquid
• Click on it to open the file in the editor
• Select all the code for the entire file and replace it with all the code from this file
• Save the file and the issue should be resolved