hello, i wanted to help with this on your site, but i just couldnt locate your emails.
i would suggest to do it one of this ways:
1. set up opc's default zip code here:
the default address will make your shipping methods display only per this address (zip)
2. you can enable the customer initialized shipping here:
which will render the shipipng by default this way:
3. you can render the shipipng methods as a drop down and with the -- select -- at the very top:
which will get displayed like this:
best regards, stan