Hah, I'm way out of my league here (I only have experience with UT1/UT99/Unreal Tournament), but I suppose there are some similarities between these games. Judging from my UT knowledge:
* MaxClientRate. In UT 2600 is for dial-up play. 5000 is for ISDN. 10000 is for broadband and 20000 is for LAN. You will find that most of the time a single client will not draw over 7000bps during play (MaxClientRate 7000), but clients do utilize the higher MaxClientRate/netspeed for downloads from the server (e.g.: downloads for which no HTTP redirect is available). I have found setting a MaxClientRate of 5000 - 10000 (depending on your available bandwidth) seems to be the sweet spot. Simply multiply the MaxClientRate value by the amount of clients you want to serve. In your case 16*5000 = 80000bps or 80KB/s (at 1000bps=1KB which most ISP's use to express their bandwidth). This means you need to have 80KB/s of upstream bandwidth available (it'd be very unlikely you have a higher upstream than downstream bandwidth
).
* TickRate. This controls how frequently the server 'ticks' per second. During a tick the game world is updated. So say you fire your machinegun, each tick would allow your bullets to inflict damage on an opponent. So increasing your tickrate beyond 20 (standard for UT) will actually make these weapons
stronger because they can inflict more damage per second. It will also increase CPU usage since your server has to work harder, obviously. So definitely leave this at its default value. This machinegun increasing strength in relation to tickrate might not be applicable to the game you are discussing, but still the basic principle holds true... There's no need to up the tickrate.