100 vs 66 tick on the net is not noticeable, just show off if you run 100 tick and wasting system resources and bandwidth. As you said yourself, there aren't many servers that can run constant 100tick over the net.
Only use for 100 tick is on a LAN where you can notice the difference.
I always say 66 is the maximum and recommended tickrate for internet play. (of course you can run 75 tick and stuff but the difference is just too small to notice)
Also flashstar, it might seem cheeper to host yourself but it really isn't
if you run a server 24/7 for 20 players at 33 tick you already need the following:
- PIV 2.0GHz or equal, 512mb ram (not very expensive and only 1 time)
- energy cost for running, this will be 25$ a month for 1 server runnign 24/7
- connection speed, you will need 1.3mbit upload connection for 20 players. (will be like 50$ at least per month)
so 25$ + 50$ = 75$ a month
Renting really is cheaper and even better is to get a dedicated server which can be around 60$ a month, you could run 4 servers on it
+ you can set everything the way you like.