Started a campaign for the CSA on very hard difficulty with historical attrition. The historical attrition is certainly hampering me but it doesn't seem to affect the AI. For instance Halleck attcked Tucson with around 10k men it took him a turn to get to Tucson he then waited a turn to attack my garison then stayed there for another 3 turns before I attacked. When I attacked he was still at full strength when he should have suffered considerable attrition as Tucson produces minimal supplies. At no point did he have any supply wagons with him. I have seen similar instances in the same campaign.
Is it worth continuing with the CSA on this difficulty level as I don't have enough men to protect my supply lines from large scale raids which could last for months if the above is anything to go by.