How to Model Finished Good with varying Weights and BOM with Conversion Factor

For example we have a Finished Good (bread packs) of varying weight say (100gm, 200gm, 400gms)

For each of these FG Variants, i have the same set of ingredients in the BOM, where the ingredients quantity vary in proportion to the FG Gram

e.g. flour -0.5kg for breadpack 200gm, flour 0.25 kg for breadpack 100gm

What is the Best way to Model This FG and BOM?

  1. Should we create separate FG Items for each weight(bread-100gm, bread-200gm, etc ) and separate BOM for each of these item?

  2. Is there an Automated way of calculating the ingredients qty in BOM based on the Weight of the Finished Good so that we need not create multiple BOM for each of these FG Variants.