I have played this game for a week steady now and have tested various diffrent configurations through the custom editor with a thors hammer controller. My configuration is as follows below and i will explain why, the akimbo mode is ok but the problem with that is with casual aim mode enabled, which is the mode that locks onto the nearest target you are facing in the game, any target can be aquired and it is usually the closest target to you but with that said as long as its all enemies there is no problem but if you get suprised by bad guys in a crowd of innocent people you usually end up killing horses,innocents and friendlies so its not very wise to do it this way unless you are away from any crowd of friendlies unless you want a bounty on you constantly. With the setup below you can enable the casual and allow target aqusition and if you do lock onto a non lethal target then simply release left trigger and swing to the lethal allowing for control of whom you gundown. If there are nothing but lethals in the area at the time or in hunting mode for example then simply hold right trigger down and continously tap left trigger allowing for non stop fire while steady moving through targets around you or simply set up your akimbo mode for this type of situation. I havent changed SPS yet to get it on the money but what im running below is very efficient. Hope this helps and i will post as soon as i have a chance to test it more.
RAPID FIRE CUSTOM-13.60 SPS .............................................EMPTY
for the alternate or second config for hunting and lethal target only areas use the following
RAPID FIRE CUSTOM-13.60 SPS..............................................AKIMBO MODE
note: these settings are on the xbox 360 system and i cannot guarantee the same for other system but they should be very close in aspect.