Tricky...but how about these ideas:

Attack after nightfall? Or at least carry out a flanking march under nightfall and fall on your enemy's flank at dawn, rolling up the line and catching all those lazy artillerymen half asleep?

Or: Form your best skirmishers into dense skirmish lines in open order, supported by squadrons of cavalry in cover/dead ground. Then snipe away at your opponent's artillery until they decide things are getting too hot...this tactic is a great deal easier if you have plenty of riflemen!! Your cavalry are used to counterattack any of the enemy horsemen who try to break up your extensive skirmish line.

Or: Divide the front into three sectors and concentrate on either the right or left flank. If your opponent has his artillery equally divided along the front then by concentrating on one point this redresses the balance and may give you local superiority. Take a lesson from the Emperor! Pin one of your enemy's flanks with some ordinary units, put your best units into attacking formations on the other flank, cover them with loads of skirmishers and as much artillery as you can spare..and go for it! If you advance hard and fast enough on your chosen flank the enemy artillery will cause some casualties but will not by themselves stop the attack.

En Avant!!

Bagration



PS: I'd always thought force majeure was a legal term...am I missing something?