I wish this game had a great combat manual. Here is my best advice on artillery that could be added to the existing information at https://betaguide.wz2100.net/SensorGuide.php
• Never forget sensors to increase artillery range.
• Mortars and howitzers cannot fire on the move. Starting with version 3.2, a keyboard shortcut allows to halt droids instantly.
• For maximum range, avoid placing artillery near the rim of maps.
• Leave a tile between artillery pieces to limit the splash damage of counterbatteries.
• Forestall enemy artillery by making use of radar detectors as soon as possible.
• Constructing mobile artillery with tracks limits the damage of counterartillery to 10%.
• Ripples are usually insufficient to combat enemy tanks or take down major defenses.
• Hellstorm howitzers are unpopular online, yet cause far more damage per minute
and fire more rounds than Groundshakers. Their downside is lesser range.