[Nightrain]

Basing that Gang Crime follows along the lines of how the game is programmed for pvp and crimes.

it would be my guess that to achieve success in gang crimes various different things would be factored in. Player general activity,individual crimes and pvp attacks.

if you notice the bigger gangs have a much higher success rate. prior to the new gang crimes added. DIS,V,SV,XPATS and CS(prior to breakup) in most cases had double or more gang members than what was needed to commit a gang crime.

With that many more members in the gang and the high activity in these gangs they can achieve almost 100% success rate.

Hence for a smaller gang to achieve a highers success rate they should attempt crimes were they have at least 25% more members than what is needed to commit the crime.
This is just something I have noticed I may be entirely wrong.