Hi Eugen,
What you can do is create seperate Microflows that are connected to the different buttons.
When clicking on button 1, MF for button 1 is triggered and provides the weight (1) to the AddWeight MF.
When clicking on button 2, MF for button 2 is triggered and provides the weight 2) to the AddWeight MF.
And so on.
Hope that helps.
Cheers,
Jeffrey