I can describe a leadership & command method that easily allows for such a corps, the span of command is no insurmountable challenge. It's basically about horizontal cooperation instead of synchronization planning, Auftragstaktik and about a different training of leaders.
Military history has seen many highly successful operations with a very small amount of directions from corps or division down to brigades.
The challenge at the operational level doesn't seem to be the span of command, but the understanding of the situation and issuing missions in a timely fashion.
An emphasis on reconnaissance / skirmishing forces helps with the former, minimal staff sizes and careful selection & training of leaders and staff personnel helps with the latter.
Bookmarks