Legs are yours to choose — the Min OI and Show/Hide filters do not apply here, and the direction is not re-derived from the rates, so you can test a side the rates do not imply. Defaults to the pair the funding tab would pick. Backtestable venues: OKX, Binance, Aster, Bybit, Lighter (Ostium has no funding; Variational publishes no history). Window comes from the Backtest window control in the header. A row's Run button on the Funding tab lands here with its pair filled in.