Prioritize shipping methods

Hi everybody

I’m trying to set up my shipping methods. Basically the shipping is calculated based on the weight.
But I in certain situation I’d like to calculate it based on the quantity.

Example: I have 5 products weighting together less than 500g which would result in 3CHF shipping cost. But because these 5 products would not fit into the small package, I’d have to use a bigger one which would result in 8CHF. How can I prioritize the shipping based on quantity over the one based on weight?

I’ve found out, that the order I set them up in the designer has an some impact, but can’t really figure out when it does and when not.

Here’s my preview Link:

I believe the shipping method order of creation is the order in which they are displayed… I’ve tried to rearrange them with code, grey out some when not applicable etc. but never managed to tweak those properly.
Would be glad to hear from any ways of doing this if someone has managed to.

The customer does not have the option to choose, because all of it is calculated. Are they also prioritized the way they were created?