Have been wondering when the server's would be changed over.

The server will not auto adjust your rate. Does Valve still default configs to 33 tick?
As far as rate's go...read up on them and the netcode to configure your own personal rates as everyone's will differ. All this means is the server sends/recieves 66 tick updates per second.

Setting your rate's too high/low will cause you choke, "lag", and other "weirdness". IE: missfireing sound, a slow response in shoot to land and more omfg hax box wall deaths. Lol.

There is much more that effects gameplay than just the tickrate.