Help with Max SM per AP

This is with regard to the number of maximum SMs that a single AP sec tor can handle…

1. Is there a way I can theoretically compute for the maximum number of SMs in a single AP sector?

2. Just by computing, how will I know the real capacity of a canopy radio assuming that a user will just use the internet for general email support and web surfing?

3. If I start adding applications such as peer-to-peer sharing or video streaming applications, how will I then compute for the AP capacity?

4. Are there documents that can help me in solving this problem?

*If you have formulas to help me solve this, please share. Thanks!

I have noticed increase in latencey at 20 users on a AP, and have noticed a decrease of throughput at 30 users, its not technical but its what i have observed.