Do you have one of those "4-in-1" "6-in-1" or "modular / reversible shaft" screwdrivers? If so you may already have the right post reomval tool without realizing it.
Most of those screwdrivers are designed so that if you remove the driver bit, the shaft will clear the full post and seat on the hex base. Some of those screwdrivers go further in that the main shaft is sized differently on either end, so give it a flip if the first one doesn't work.
Way handier than fumbling with ratchets and sockets, and those screwdrivers are cheaper and more versatile than a dedicated tool.