*really long post*
Fair play to you for posting that, took a lot of effort I imagine and has been a topic I've been surprised not to find more information on in the past, so good to read.
How did you identify clubs who had signed 6+ players, or clubs who had lost a key striker - your own knowledge, or is there some kind of database you're working from?
Also, did you look at what happens when you sign 6+ players AND lose your key striker? I imagine the n size is too small for meaningful comparison. But that's the situation we're in.