Spent 2 weeks building an honest SPY short-vol backtest. Same cell did +5,400% with a stop and -100% Hey guys, been heads-down for the last couple weeks building a proper SPY put credit spread backtest and I think I have a few findings worth sharing. Posting the highlights here, full writeup with all the tables and numbers is linked at the bottom. **TL;DR - what made the exercise very difficult was adding realistic fill simulation. Every strategy that was making +5,000% suddenly started stopping out on drawdown or going outright bankrupt.** Once the simulator stopped letting me fill at the mid, half the "winning" cells flipped negative. Once I added a stop loss, the cells that had been wiping out flipped to category-leading. Almost everything I assumed was either wrong or required one specific guardrail to not blow up. # Setup * grid cells across (delta, DTE, profit-take, stop-loss) * % drawdown circuit breaker that just halts the whole run when things go bad # The eight findings **1.…