The 1 minute poll time for texts is probably a bit much, but not because DC/TOR will take up too much processing time or the network traffic is much. To save battery, the phone software actively tries to put the network stack to sleep. If you keep the timer at 1 minute, it's going to wake up the stack every time. Unless you expect immense texting, I recommend 15 minutes or more. The lowest I have ever used is 5 minutes.