Execution data is there but buried
Everything I need to evaluate my own fills exists. It takes four steps to get to it and one of them is an export.
For a metric that determines whether a thin-edge strategy is viable, that's too far from the surface. I'd put average slippage next to average return, because they're the same importance and only one of them is visible.
The data being available is the hard part and that's done. The remaining part is deciding it's important enough to show.