Keyboard Maestro is a very powerful and easy to use keyboard macro app. If you want a multi-step process available everywhere on your Mac you can't do much better.
By "multi-step process" I mean, to use your example, no matter what app I'm using right now, pressing a certain key combination performs these steps.
- Quickly switch to the Wire Tap app.
- Press CmdShiftT in the Wire Tap app.
- Quickly switch back to whatever app you were previously in.
This all happens so quickly that you can barely tell any app switching occurred.
I use it to start and stop my time tracking app at the press of a keystroke, for instance, as well as ensuring that Cmd+ zooms in no matter what graphics app I'm using and Cmd- zooms out.