Storefront header height & woocommerce product search widget

Dear all,

I’ve been using Storefront & Woocommerce for a while and was wondering if anybody managed to do the following customizations:

1. Adjusting height of the header section, where logo, secondary menu and woocommerce product search are located;

2. Adjusting the height of the main nav which goes right after the header with the shaded background;

3. Adjusting the styles of woocommerce product search widget?

I was searching for tips and tutorials online and on wordpress / woothemes sites, but with no luck.

Help would me much appreciated.