standard model - The charges of the forces

I am trying to establish a simplified understanding of the fundamental forces to explain them to a young audience.

If we say that gravity has one charge (attractive), electromagnetism has two charges (positive and negative), and the strong force has three (red, green and blue), what does the weak force have? I understand it would be something to do with isospin. Is it two, like electromagnetism?

Extended question: The reason I am doing this is because there is a problem explaining gravity as weak. Kids respond by saying, "if it's weak, then how can it swing big things like planets around?" I realise that explaining that it is only additive is very important.

So I am thinking about a simplified system to explain the force's attractive power (as opposed to another 'rating', which would be quantum power - where the strong force is 10/10, Gravity is 1/10, etc....)

Gravity would be 10/10, as its only additive - Electromagnetism would be 5/10, as it only half attracts and half repels.

In this scenario, what would the strong force be? 3.3/10, or 6.6/10? I imagine it is the latter, as red attracts green and blue, not one or the other.

Of course, this is problematic when it comes to the weak force, as (as far as I know) it does not play a role in binding things together. So maybe the best rating for this one is n/a (not applicable)