I'm not sure if you were referring to me but it's less of an objection and more of an inquiry. Purpose made headset wrenches have worked great for me in the past. Crescent wrenches... obviously not, especially on black locknuts. Not having tried an adjustable hex wrench, I wasn't sure where that would fall on the continuum. If the use of such wrenches is common practice, that will be an attractive option for me.

Is there a particular wrench that you've had good experiences with? Amazon has three versions, in order of price (CAD):

Max Power @ $29
Rigid Tools @ $58
Milwaukee Tool @ $58

All seem to be rated about the same. That said, I imagine that bicycle work is not the most common usage for these things.