Sure, I’m just sharing the settings that I use and that empirically work for me.
Best practice is difficult with so many different system configurations, geographic separation, rclone versions, undocumented tweaks on Google’s end, etc. I happen to be able to see a Google data center from where I’m sitting and I coordinate three machines across two different countries, all with different purposes. Other people will have other circumstances and, hey, maybe my exact settings will work best for them—maybe not.
My sweet spot is best average performance with a very heterogeneous set of files that varies wildly between batches and they are delivered to multiple endpoints. For me, zeroing out 403s would not necessarily improve overall performance, but it would require writing separate functions for each specific case, which adds complexity and is error-prone.