Shoulder to Shoulder

I have been watching some videos on open battle fighting. I came up with an idea that if two or more inf. units are standing shoulder to shoulder and at full 4 figures, and on open ground, that they get i more dice to roll . This would only be good as lone as each unit stays at full 4 figures. Units that lose 1 figure or who get a flag, do not get the extra dice. I tried this as a house rule and liked it . Please let me know what you think of it.

What does exact mean "shoulder to shoulder", only adjacent, or vertical adjacent?

And what are the exact battledice, 5-4-3-2 instead 4-3-2-1 ?

I will try it next, but BC has already the most deadly rules, so one die more (so they would have ART stats), is absolut deadly....