Goodness-of-fit metrics mapped across separation and number of principal components. The colour scale indicates median metric value from the injections at 4 separate position angles. The range of the colour scale for each sub plot is different in order to capture the variation within a single map. Highlighted in red are the optimal extractions for each separation. Left: χ²/n_data map. Right: the same as the left panel, but calculated using the relative discrepancy (e) instead of the χ².