Question about Clan War matchmaking

I became curious about the clan war matchmaking. First I've read that trophy does not influence clan's strength, and the clan's strength is the total power of troops, defenses, walls, heroes etc. I think this is fair, and SC made a great choice putting trophy out of the matchmaking system.


Now this is my question.
Let's say our clan has 45 members, opponent has 49 members.
we will go 45 vs 45. In this case which one is the clans strength?


1. "total strength"
All 45 members strength added VS all 49 members strength added.
This will usually mean, more members make the clan more stronger.


2. "average strength"
All 45 members strength added and divided by 45 VS all 49 members strength added up divided by 49.
In this case the amount of members do not influence clan's strength. This seems more fair to me.


3. "the top XX players total strength"
For example, top 20 member's strength VS top 20 member's strength.
This will also mean the amount of members do not influence clan's strength, neither the bottom players strength. Better than number 1, but imo it is unfair to exclude strength of war participating members.


4. "war participating member's strength"
45 members strength vs 45 members strength.
Better than 1 or 3, but the excluding lower members strength in the "clan war" is somewhat weird.



I think 2 seems fair, but really which one is the clan's strength?