This working paper describes developments on the Indian Ocean Tuna Commission (IOTC) bigeye (BET) reference set and robustness test operating models (OMs), with key Management Procedure (MP) evaluation results, since the 2019 Working Party on Tropical Tunas (WPTT) and Working Party on Methods (WPM). In the following (for historical reasons), we mostly use the term MP and Management Strategy (MS) interchangeably, though we subscribe to the specific definition of MP as a subset of MS (as defined in the CCSBT and IWC, in which the MP aims for full specification and simulation testing of data collection and analytical methods). Management Strategy Evaluation (MSE) is the simulation testing process, using complex operating models, for evaluating performance of alternative MSs (or MPs). The intent was to obtain feedback on presentation requirements for the 2020 Technical Committee on Management Procedures (TCMP) meeting, and recommendations on further analyses and revisions for the OMs in preparation for the WPM and WPTT 2020 (but priorities changed due to the Covid-19 pandemic and remain uncertain).