For surfacing, here’s a zig-zag pattern for a #201 on a Pro XXL (should also work for an SO4):
surface_slat_pro_xxl_origin_front_left_0_001mm.c2d (12.2 KB)
v7 file:
surface_slat_pro_xxl_origin_front_left_0_001mm_v7.c2d (44 KB)
Just set the origin at the front left of each slat and run it — I mark each w/ a zig-zag pencil pattern, use a level to pick which one is lowest and start w/ that one for Z then I jog over and only change the X origin for each other slat. Repeat until all pencil marks are gone.