Hello @GoMurica
When thinking about density, I always try to think about having more smaller cells rather then 1, 2, or 3 large cells. It may sound counter intuitive but turning the signal strength down may help. Think of it this way, imagine in that same space each AP that is mounted is a loud speaker. If each and every loud speaker is running at max volume, you will have a hard time making out any one message from the speakers. If you turn all of the loud speakers down, as you walk through the room the speaker closest to you becomes more clear and you can make out the message. The above analogy should not be confused with interference, RF utilization, just encouraging roaming if you will, the client has to have a reason to roam and that comes down to signal strength.
A few other questions I might ask are:
1. The APs are using different channels correct?
2. Are you using both bands and are you using band steering?
3. Is 2.4 needed on every radio if used at all? Are you only using 1,6,and 11 for 2.4?
4. How large is the space?
5. Are the APs mounted 25ft or higher in the air?
6. What kind of client density are you noticing per AP on average?
7. How many APs do you have in the space?
To answer your question you cannot put a cap on the amount of clients.
Ryan