Wouldn't a small strap wrench also work? They make smaller ones these days that should work with the diameter of headset lockrings and top race bodies, specially chunkier ones like that Mavic 310. Straps on them are pretty strong, so I think there should not be any problems generating enough torque to remove most of these lockrings. I suspect you might be able to use it to install/tighten them too. It should be enough torque as I don't think these aluminum lockrings/top race body could not take as much as their steel counterparts anyway, so required/expected final torque values must be lower that what one might used iwth steel.

Chombi