Socket diameters can vary, by quite a lot, for both metric and imperial tools. Depends on the manufacturer, type of steel and expected use of the socket. Oh, and cost.
vscid - Tolerances for metric wrenches are listed under DIN 475-2 or ISO 691.
If you need just a few - post what size and I will get it for you. If you need many sizes - google and you may have to buy a book. Best source - "Beuth" ask for their English version of DIN 475-2 or ISO 691.
Realistically, can you really expect your "average" mechanic or millwright to have a socket in his toolbag that is so close to "not fitting" - given the above where socket walls between manufactorers and suppliers so differs greatly! - that you (as an original designer) needs to consider fabrication tolerances in order that HIS socket will fit between YOUR nuts?
I think you need more space. Or a specific, designated socket wrench YOU will supply WITH the machined flange YOU are selling that will permanently stay with that flange for as long as the flange will need maintenance...
Looking back I guess my question was not clear. I was looking for the standard clearance range between the flats of a open faced wrench and a nut/bolt head (DIN 475-2). I would like to use a hex head bolt in a non traditional way and want to insure that there is never an interference, so I figure the easiest thing to do is mimic the clearances on a wrench since there is never an instance were a wrench does not fit a nut/bolt.
So again sorry for not being more clear, and making you waste your time with an answer that is not applicable. Good day