Start with your 20min test split +10", then go faster by 1-2 for every rate shift. Aim to be at your 20min test split number once your get to 1' @ R24 stage.
Day 2 Erging. Warm up for 18min. 3 ' rest
R24 power pieces
8 x 1min R24 / 2'rest
Day 3 Session on the water. Warm up for 25min (Steady state with technical focus and power pieces)
2 x 3000m (Rate shift every 500mR18/20/22/24/26/28)