Being from home of KLM you should be looking at FB as your FF for better TATL upgrades.
When it was NW/KL alliance I, as a NW/WP Plat was given op-ups TATL many times when coach was full. KL/AF does not extended the same generosity towards DL SM PM.
DL does not upgrade TPAC TATL or HI flights unless the Y cabin is full.