The sledge build maybe is the most simple one you can choose.
It consist in just 2 units: the sawmill and the sledge workshop, no energy required.
One sawmill provides 5400 CBMs of wood per hour, enough to run 18 sledge workshops ( who consumes 300 CBM per hour each ).
No waste of any kind as output.
1x sawmill ==> 18x sledge workshop = 7560 CBMs of sledges per hour