You can use templates in your theme to further customize Button Variations, just add the following files to yourtheme/woocommerce/woocommerce-button-variations/ (create the folder if its not there).
From the plugin folder copy for displaying of variations:
- woocommerce-button-variations/templates/variable.php » yourtheme/woocommerce/woocommerce-button-variations/templates/variable.php
To change the stylesheets that add functionality (like button size) to buttons:
woocommerce-button-variations/css/wc-ea-css.css » yourtheme/woocommerce/woocommerce-button-variations/wc-ea-css.css/
- woocommerce-button-variations/img/checkbox.jpg » yourtheme/woocommerce/woocommerce-button-variations/checkbox.jpg
The default size for buttons is 32px high and 64px long. You can setup a different size going to the css folder (requires you have access to the file system of your host).