Trouble with shipping by weight by country

[benwiggy]

I'm just trying to get to grips with ZenCart, and on the whole, it's seems great. However, I have lots of newbie questions that I can't seem to find on the Wiki. Is there any other documentation?

Firstly, I want to charge shipping according to weight, AND according to the destination. So sending 10 widgets obviously costs more than 1 widget, and sending it to Australia costs more than sending it next door.
I've set up Zones for UK (where I am), Europe, USA and Rest of World, in the Location/Taxes bit, but that seems to have no bearing on the Zone Rates in the Shipping Module.

I've put in rates for different weights in the Zone Rate Shipping module, but when I test it with a test purchase, it says "Zone Rates cannot be determined at this time". It also still offers them the option to have free shipping, which only UK orders should have.

Secondly, is there any way to change the weight from lbs to kgs? It doesn't really matter from a calculation point of view, but it just looks odd if everything is half as heavy as it should be.

Can anyone point me in the right direction to find out more? Many thanks.

[benwiggy]

Sorry to Double post: one other thing:

I've used weight values that are under 1 (i.e. 0.3, 0.5.) Is that allowed?