Radial surface field strength as a function of the cooling age of the WD for Scenarios B (blue) and C (red). The shaded regions show the evolution for varying field strengths on the RGB between 10 kG (bottom) and 200 kG (top), the range detected in Hatt et al. (2024). The dashed line shows the emergence of the strongest detected RGB field of 600 kG (Deheuvels et al. 2023) and places a lower limit on the FFS emergence timescale. The white circles show detected magnetic WDs from the Bagnulo & Landstreet (2022) and Moss et al. (2025) samples in the mass range [0.5 − 0.64] M_⊙.