I've done this in stage before with a BR. It's important to note to the client that numbers in stage won't tie to the source data (bc you've translated it). The alternative you have is to use the out-of-the-box functionality in flow. Load translated, derive local. The idea is pretty straightforward, you load data to a flow member and OS will translate to local.
you'd need one flow member for the loaded data and one for the local data. it works just like the out-of-the-box override functionality but opposite. it looks up the entity currency so don't need one for every currency. nor do you need special accounts.
