Well, 8 and 5 inch shells have the smoke trail behind them (which I have never seen in any WW2 Doc or present). You would not need to know what direction it comes in. For example-Say y call in a grid coordinat (lets just say they provide an Arty Batt for certain fields etc..u would use the current Grid Ref Coord i.e 17,8-5 and then turn that into its own grid box so would do the same for more precise drop). You would see the round impact, and then would say "round short 200m, add 200", then another smoke (i.e. Willy Pete round). If it hits close to twn center or say 100m away, u then say " add 100 Fire for Efect" and WHAM, all rounds following should rain down right on town. Thats how the Miltary currently and since Arty was used on the battlefield had done it. Know its a little complex, but would make for an interseting aspect to the game...