Gain in RV jitter in various conditions. Upper panel: gain vs. RV jitter (for simulations including rvogs and rvinst, and for ΔT_spot2), for a correction with alone. The straight black line has a slope of 1, indicating points where the correction allows a residual RV jitter of 1 m s⁻¹ to be reached. The colour code corresponds to inclination, from pole-on (i = 0°, yellow) to edge-on (i = 90°, blue), with light and dark orange corresponding to 20° and 30°, light and dark red to 40° and 50°, brown to 60°, and light and dark green to 70° and 80°. Middle panel: same for a correction with and a second-degree polynomial in time. Lower panel: gain with and time correction vs. gain with correction only. Only one point out of five is shown for clarity.