How to Increase Experience Gainning Rate

Could someone please give me a hand on that?

Is it possible, by scripting or not, to make units gain experience faster during campaign battles?

Some of my infantry units have crossed weapons with the enemy for, let's say 20 battles and, they are only level 3 of experience ... Very boring!!!

Can't. Hardcoded.

I found that when I made units stronger and units smaller , they seemed to gain xp a lot quicker.

I think it's at least partly linked to "units killed" to "men in unit" ratio.

Maybe increasing HP for elite units might go a long way.