Stacking Question

I'm trying to grasp stacking in CoW but I'm not finding answers about stacking artillery, rocket launchers and AA.

10 best units deal damage. That part is easy.

I understand that the damage percentage is calculated with unit numbers.

Ex.: 10 units dealing 20 damage against 2 units. Each defending unit takes 10 damage each. (Over simplified explanation, but the logic is there.)

But, what about the examples below:

Stack composed of 10 Arty and 10 Infantry attacking 1 infantry

1. The arty deals the damage because of range?
2. Will the infantry count towards damage calculation or the 10 Arty will deal 100%?

Stack composed of 10 Arty and 10 AA defending attacking 1 bomber

1. The arty deals the damage because of range?
2. Will the AA count towards damage calculation or the 10 Arty will deal 100%?

Stack composed of 10 Arty and 10 AA defending defending 1 bomber

1. The 10 AA will deal 100% damage?
2. Since this time, arty can defend against the bomber, will it count towards damage percentage calculation?

Stack composed of 10 Arty and 10 rocket launcher attacking a stack composed of 1 infantry and 1 tank

1. The 10 arty will deal damage to the tank and 10 launchers will deal damage to the infantry or the damage will be 50% of total damage (5 of 10 arty against the tank and 5 of 10 launchers against the infantry)?

I found an over explained text about damage calculations to compare and understood that 10 arty would deal 15 damage to 1 infantry. But in a stack of 10 arty and 10 AA, it would be 50% of the stack, the damage would be 7.5 damage. I found easier to see as 5 arty dealing damage. Or would the 10 Arty attack dealing 15 damage to 1 infantry, ignoring the AA? If I got it wrong, care to explain?

What's the best stacking practice for damage output and/or survival?

1. One stack with: 10 Arty/10 Launcher/10 AA (Over stacking)
2. One stack with: 3 Arty/3 Launcher/4 AA (10 unit stacking)
3. Two stacks with: 6 Arty/4 AA and 6 Launcher/4 AA (Split Stacking)
4. Two stacks with: 10 Arty/10 AA and 10 Launcher/10 AA (Split Over Stacking)

I understood some things about damage calculations. But I couldn't find explanation about this examples I mentioned. Most examples were about fighter and bomber calculations and every time someone explains about artillery, it only tell to 10 artillery stack behind defenses and to protect it with AA. But never mentions the stack numbers.

Thanks in advance for any help and for the time spent to read.