Thanks for the feedback!
With multiple objectives, it depends on their relative positions. Usually I'll go for a left or right hook, using artillery smoke to protect the open flank and a small holding force to watch out for counter attacks or mobile forces that I haven't previously spotted. Concentration of forces is very important to gain local superiority.
I tend to save my artillery for smoke barrages and attacks of opportunity when you spot infantry in the open.
To defend against artillery is a bit more random. If I have an armoured platoon that has been stationery (or not moved far) for a turn or two, then my next order, wherever possible, will be a Rush. Their previous position will frequently get carpeted
It is imprecise though and you will occasionally get caught with your trousers down! Infantry are less mobile and more fragile, so I try to keep them moving or in hard cover. This is not always possible so you have to accept that occasionally you'll get hammered.