The battle of Hagelberg. Preliminaries

I have started the re-fight of my version of the battle of Hagelber using divisional Napoleon's Battles (NBd). After laying the terrain and enroling the units (finding incidentally than I have not sufficient Landwher figures for all required battalions and that Line Prussian figures must be used instead) I have played three NBd turns, i.e. approximately one Napoleon's Battles (NB) turn.
I have found the first and expected problem: the artillery is too powerful. In around 30 minutes, the French guns have dispersed two Landwher battalions whereas Russian artillery has routed and expelled a Croatian (pro-French) battalion from a loopholed farm.
The conclusion is obvious: the artillery hitting power must be decreased. In the next turns I'll apply the same rule than for skirmish fire: "a two-losses results is converted to one-loss, and a one-loss result is a miss".
I'll continue the play during the week but until the next long week-end (thursday to sunday) the battle will be not finished. Until then, you can see Girard on the Windmühlberg hill as he's watching (with some apprehension?) the approaching Prussians.