I rode LEL in 2005. Most riders' approach is 300 km per day with the last day 200 km. The only problem with this strategy is that you will be competing with a lot of riders for a limited number of beds. I'm not sure if those particular checkpoints have the most beds available (only some checkpoints are youth hostels).
After 4 x 1200 and 1 x 1400, my first day is usually fast, the second slow and usually the third and later are in between. YMMV. My riding average is usually 22-23 kph averaged over the length of these events.
The slower minimum average speed of LEL (constant last time, not a fast first 600 then slower) allows more sleep, a significant proportion of riders virtually avoid night riding altogether.