Like I said, if your gyro doesn't have a limit adjustment, there's no way to adjust it directly (actually, a programmable digital servo might let you adjust it also). But the travel adjust on the radio may limit it in flight to some extent. If you aren't telling the gyro to piro as fast, it's generally not going to have to move the servo as far unless there's a gust or something that it tries to correct.

BTW, if you can increase you head speed it might help your tail problems.