You can try HiCLift? The software was designed to convert genomic location between different genome build (ex. hg19 -> hg38), but I think it can solves your problem.

Here is the code snippet to add the weight column to the bins

weight = cooler.balance_cooler(clr_name)
with clr.open('r+') as f:
      f["bins"].create_dataset("weight", data=weight[0], compression="gzip", compression_opts=6)'

This code snippet adds the weight column permanently to the bins. you can check this by the following code example

claname.bins()[:]

Alternatively, you can use the command line cooler balance <clr name>for each resolution. This also adds the balancing weight column to the cooler file permanently