How to generate choices for constant sum from previous text entry question?

Hi, I encountered a problem. For example, I have a text entry question here requiring participants to input some factors with commas.
Then, I put the input in the setEmbeddedData(). I have a constant sum question follow, requiring them to indicate the weights for those factors. The choices are generated from the input text splitting by commas.
var answers = Qualtrics.SurveyEngine.getEmbeddedData ("Answers");
var choices=answers.split(",");

How could I generate choices in constant sum according to var choices? The number is not constant, so it's confusing me.

Much appreciated!