You have the BG culling (if needed) correctly identified. Cull med sized BG if needed leave the largest (esp. males) alone.

On LMB culling is different. Cull poor specimens from each size group (year class) especially from the group that are too numerous. Keep in mind that often the male LMB are smaller. I don't cull my first stocked LMB or BG because they were stocked to the right numbers.