Artillery in CMBN is a powerful factor but not insurmountable. If you keep your AT guns keyholed, well concealed and quiet (at least until the tanks roll) they can survive long enough to do some damage. Other units have to remain mobile. Have two or three backup positions for your HMG teams, tanks etc. Once the first spotting rounds of an arty strike start falling pack up and move out. The real backbreaking artillery assets (105 MM and up) all take a pretty long time to call in. That allows you to stay ahead of the barrage. Of course on a small map with only so many viable defensive strong-points this may be easier said than done. Here's hoping for more sprawling battlefields in future modules.