Change weight depending on option

Hi,

Maybe this is already in the cart and I'm missing it somewhere, but say that I have a product which is available in two different weights how would I have this as one product with options. As far as I can see, there is one opportunity to add weight, and it never changes.

But some products are available in different weights but yet are exactly the same product otherwise, does this mean I have to add the product in several times?

Thanks

It looks like you need this: Options Plus.

What does it do:
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This contrib adds additional parameters to Product Options.
Options now have their own levels of: stock, weight, subtract flag, SKU, description, and image.