Sounds to me like you are in a good range when it comes to magazines. Obviously, there are other opinions. I would now focus more on ammo or other items your rifle may need. If you find you are getting to a place where some of your magazines need to be replaced or just come across a deal too good to pass up, then, by all means, add a few magazines to your stash.
As you have noticed, there really is not a right or wrong answer to this.
I married my wife for her looks; just not the ones she gives me when I bring home a new gun...
Pick a container to hold X. In your case X=AK mags. Fill said container to overflowing. Store container, find new container for the part that overflowed. Repeat. Realistically I shoot for about 10 for everything but I always end up with either 2 or 25. My containers for pistol mags are pencil boxes, my container for rifle mags are the shoebox sized clear plastic boxes.