This is a very short project:
We need for our store correct shipping zones and weights setup on checkout for each country.
We can provide the zones and rates.
Will pay only $20 for this project as half the work is already done for you.
example
units less than 500g to UK 5.99, to Europe 9.00, USA 12.00 Worldwide 14.00
Each unit 1600g to UK 9.99, to Europe 15.00, USA 18.00 Worldwide 20.00
2 units 3200g to UK 13.99 to Europe, 32.00, USA 35.00 Worldwide 40.00
3 units 4800g to UK 19.99 to Europe, 45.00, USA 55.00, Worldwide 69.00
4 units 6400g to UK 19.99 to Europe, 55.00 USA 65.00, Worldwide 79.00
you will also need to edit the product weight for each of the category's.