Ohh I see, that's a good idea! That way I can keep presure until they break.
You might even get away with using armor in the mountains (for low manpower losses) if you have enough CAS in the area (CAS don't care how fortified your enemy is). So you'll need as many spare divisions as your supply situation and IC would reasonably allow. Trick with taking mountains and such (other than getting around and ignoring until they starve) is to press the attack so that enemy won't re-org and new divisions won't fortify. As for exact number: see how much line artillery would give you compared to support artillery and how high penalty you'll get for mountain attack.
Originally posted by Sir Edward XII:Thank you for the detailed reply! So from what I understand im better off using AT and Artillery on the support column rather than attaching them directly to the brigade? And using mountaineers to fill up the combat width? Generally - yes (especially in smaller width divisions).