Shipping to country (now) vs. by product (better)

An example: Shipping to USA.

I have a poster that I want to ship in a tube, for which I will charge $5.

I also have a sticker that I will ship in an envelope for which I will charge $2.

Right now, any product shipping to the USA zone, even if they are alone in the cart, will show both shipping options. Every single U.S.A. shipping option shows no matter the product, and yet, I don't want a large box to be a selection option when shipping a small item, or for an envelope to be an option when shipping a bigger product.

Using classes is not an option either. The Classes work great as a shipping supplement. e.g. Heavy and bulky, let's add $10. It does not offer a choice.

Thoughts? Anyone?