I was at the range today at lunch and remembered that I had gotten some impact tape from some balls I bought a year or two ago. I dug it out of my bag and took it with me to the range.
After warming up, I started to hit some driver shots and hit a few popups and then some pretty solid hits (yes Yoda I am working on those downswing waggles!). I decided to try the impact tape (little oval stickers that attache to the face of the club that turn blue when a ball compresses against it) with the driver. Right away I noticed that my hits were at the very top of the driver and towards the hosel. I then stood a little farther away (set up the driver so the toe was at ball level when it was soled) and didn't flex the knees as much. I then started to hit closer to the middle and a little bit further down (not quite the sweet spot yet but closer). The amazing thing was when I did this I started gaining 30 yards on my drives with the same swing -- hitting close to the sweet spot makes a huge difference.
I would highly recommend impact tape for seeing where you are hitting with your irons as well as the driver and fairway woods. Do a google search for "golf impact tape" and there are several options for well under $10, including a non-harming paint that can be wiped off that performs the same function.
Anything that can provide useful feedback to your swing while you are training is a great idea IMO...I use the tac-tic reguraly (to monitor the FLW) and will start using the impact tape as well.