Fighter group size

[Q]

The default value for fighter Groups is 5.
In my opinion this may not be optimal for two reasons.
First a group of only 5 fighters may be incapable of damaging organic or crystalline armor (unless using rocket pods) and if you have a lot of fighters in a combat the field may be so much crowded, that not all fighter Groups get into firing distance.
Second if you have a large number of fighters in small Groups it becomes very complicated for the computer calculation. The time for combat calculation goes up very much and sometimes the game even locks. This may be less a problem with powerful hardware, but the reported problems with SEIV in later games may partially be connected to this.
So I set fighter group size to 20 or even 30 and I don't see any disadvantage.
What's your experience?