Using the Monk AC mechanic for D20 Detectives Handbook

[Sidran]

the Great Detective, and other Steampunkish Classes such as Constable, Master Forger, Doctor, Murderer, Medium

The Detective's handbook is set in the age of Sherlockian London
No one wandering around in armor in the 1860's

So I have hit a block with the AC issue, Should I use the Mechanic that is used for the monk or should I do something else

 

[comrade raoul]

You'd probably want a VP/WP system and Defense Bonuses for a setting of this sort. See the Star Wars or Wheel of Time RPGs for details (I think AEG's Spycraft uses this system too.)