I have some comments regarding the level issue.
In the first place, I would rather have a seperate server (PC based) only doing authentication ie UserManager. This server should have the Level6 license installed. On your high sites, hotspots etc, you only need level4.
In the second place, UM is under development, and is offered free of charge. 10 users are more than enough to test with. If you need to implement it on more than 10 users, purchase a higher level of license. This will help MT make more money to invest more time in the development of UM, thus we all score. However, I do agree that level5 should have about 50 active clients too.
I have setup several hotspots using UM and MT Hotspot. Luckilly we still haven't run into problems where there are more than 10 clients connected at a single time, but it will most definatelly happen. Espesially if you have more hotspot AP's. Almost all the clients I have setup these hotspots for, will never have more than 30 clients at the same time, but they'll more than likely have more than 10 at a time. 50 is a good number for a L5 license.