Most of the time, two weeks is fine.  Sometimes we want a longer historical view, particular when working as a patch manager for older releases.

Having some way to say, "give me this sippy page, but with three months of data" would be really useful.  Taking multiple minutes to for the report to generate is ok.

Grafana dashboard?
Standalone new API for test details in sippy querying bigquery?

SQL scripts?

Use deduped junit table in either case.