Your own A.I. is actually pretty good. First you have to play enough games to get some really good ribbons. Then you troops will begin starting out with better moral and rifle skills. As troops gain exp they become increasingly smarter. Remember to use concentrate fire and stop fire when needed.
Its actually max squad limit 6 or less to avoid all airstrikes and arty strikes(still a really low chance of them still happening). With the new camo net addition you can add more troops as long as 6 max are outside of the camo net.
The last game i played i only had a 6 man squad though the Germans still sent arty at me(killing everyone with the first hit....-.-). Though every time before that no arty or air strikes with 6-man squad.