Vipper I'll think you find arty commander flares are useless because all okw players ranked above 500 will build a Howie next to their base sector behind flak HT.
If they are building lefh on frontline sectors they must be a pretty bad newb.
Ignore vippers advice and go for balls deep smoke spam with a unit direct and off map call in arty. Hans often does this with a sneaky AEC or Cromwell and it seems to work well. Pretty sure he mentioned this in his training series.
reasonable tip