Eventually for my own work, I discovered that the context management and runtime was more like a stream or active service mesh than a dispatching / one-off processing problem, most others' were too. Then all my prompts would degrade across model versions or providers, and I realized that actually setting the context for the tasks and keeping track of it all was a ton of work and something I had to do everytime as an actual user, but never when I was testing or demoing it on existing data.
Curious how you're testing your work and if you've managed to avoid the problems I ran into. I need to permute across the same set of workloads/configs you mention (and maybe more) for my next set of work so I'd be very interested in sharing or collaborating on the test infrastructure! At Google I did a lot of permutation testing using https://github.com/cloudprober/cloudprober and was going to start using it sometime in the next couple weeks. It exists basically one layer above the workload content/targets so it's probably compatible with everything except the test client/driver you're using.