Box Sizes for CF7

I have two forms on a site I am building and the boxes are all different sizes. I have tried stating the width of the boxes as a % but 80% for one box does not match 80% for another.

Forms are on http://roofer.colintonwebsitedesign.com/ and http://roofer.colintonwebsitedesign.com/contact-us/

Would be grateful for any advice.

http://wordpress.org/plugins/contact-form-7/