gatrm wrote:
It will hurt your dps if you simply target through the tank. You want to make yourself a macro that you hit once the tank changes targets- you might need to get used to how your tank is tanking/changing targets, and it takes some practice. If you start climbing too high on the aggro meter, you can always change targets. The macro will say /assist tankname
Great suggestion! See even old dogs learn something new. 
Now I just need to find an open slot in my hotbars. 