If you're going to do any adjusting, you should do it with the rear sight. I tried to do it on the front sight and actually broke a piece of an allen wrench off in the screw. I talked to Taurus and they said to always move the back sight on the 24/7's.
Anyway, I think the rear sight screw uses either a 2mm or 1.5mm allen wrench. You probably need to do something to loosen the loctite they put on the screw at the factory. Heat seems to work best for most. Some have had success using a hair dryer, but I couldn't get mine loose that way. I eventually used a solder gun to heat it up and then it broke loose with the allen wrench. Then you can adjust it left/right as much as you want. You're going to want to loctite it back in place when you get it where you want it.
Hope this helps. Shooting to POA is the biggest problem on the 24/7, IMO. If you get yours to shoot to POA, it's a great gun.