Email, call or send a message from the above mentioned link. You can also call Bob directly if you want to speak to him about your order (972-849-9240). I have spoken with Bob myself and he is VERY accommodating and customer service oriented.
I highly suggest getting the Super High Wind Gizmos (SHWG) with the Velcro end option. As the name suggests, the straps on the SHWG do a great job keeping them on the bunk ends on windy days. The Velcro options help to keep the roof end of the Gizmos tucked under the roof. You will have to purchase and apply the matching Velcro under your pup's roof yourself to secure the Gizmos, but it is well worth the extra $5 per cover.
BTW, my pup is one of the pups that is pictured on the Gizmo Media gallery Media Gallery.