Yep I think a google doc is a good starting place (as @emdupre mentioned - BIDS standard/extension for storing QC information). Perhaps a few recent BEP examples to reference, a recently officialized BEP (BEP31: Histology), started here with Chris M.'s comments a few posts below. We also had BEP29 and BEP30 were recently made official BEPs too. These examples can help formulate your BEP and move it forward.
Thank you,
Franklin