[philsnow]

> Or I could simply include the last build's assets as there's no conflict potential.

It looks like your build puts the hashes into the file names for each asset (instead of just naming resources purely as the output from the hashing function). If you're using a halfway decent hash function, you're ~never going to get a hash conflict even across all of your assets, let alone across all the versions of an asset for a single source file name.

You could just leave all the old assets in place (esp because many of them won't change from build to build) and prune hashed assets that you know haven't been referenced from an index.html in >1 month.