This is a fiddly one to explain, so please bear with me.

I'm setting up a furniture store, which delivers goods via a few delivery options, ranging from sending a garden gnome in the post for £10, or shipping a god-almighty granite fountain that requires two hefty blokes and a lorry to get it anywhere, cost dependant on location.

I'm thinking of modding the registration page to have a drop-down for their location, so we can allocate each county (this shop ships to the UK only) into a shipping band.

The delivery options for each item are specified from a drop-down attribute list, when the product is added to the cart, and only applicable options are added by the site owner. With some options, the actual delivery cost depends on which shipping band they live in, and in one case there is no shipping charge, as they have to call the bloke running the shop to agree it themselves and pay for it seperately. The actual cost of shipping is determined by the highest value, and the others are then free. As I understand it this even applies to bunging gnomes in the post, so that's not a worry.

Now, I'm a fairly good developer (or like to think so anyway :)), but I'm not that familiar with the inner workings of Zen Cart, having done mostly cosmetic stuff with it before. So, the question is, what would be the best way to go about implementing the above? I thought it better to ask you lot, rather than take a pop at it myself and potentially take a route that may prove long-winded and harder to maintain in the long run.

Many thanks in advance. :)