Shipping per Categories

[missinglife]

Can anyone help me out with shipping?

I recently added a new category, which have items that are very small, does not cost a lot to ship, so I need different ship fee for this category, but other category will need to be not touched.

here are the two categories that need shipping fees:
1. Waterslide Decals
2. Nail Art Waterslide Decals

I set #1 category as zone rate because the items are large, so shipping fee set at $2.50 US per sheet, Canada is $3.00 per sheet, and Rest of World is $6.16 per sheet.

now I add the new Nail Art Waterslide Decals, which are very small items, which will have less shipping fee, for example, US shipping will be $0.46 per sheet, Canada will be $2.00 per sheet, and rest of world will have $3.00 per sheet.

by the way, both categories, I set item weight to "1" (not sure is lb, or oz).
How do I set up the shipping modules so I dont over charge customers for #2 category?

Thank you so much in advance.
here is my website if you needed: http://the4thmuse.com

by the way, should I upgrade to newest zencart?

Arwen