Strings position on the garment

"The hole to place the tzitzis through may not be more than three thumb breadths (approximately 2.25 inches) from the bottom of the garment33 and not less than the length from the first thumb joint to the tip (approximately 1.375 inches)34, so if the garment tears in the corner area, the tzitzis will still be attached.35 If the hole is outside of these parameters, it is not considered in the corner of the garment. These measurements are done vertically, not from an angle.36

The strings must be spun for the sake of the mitzvah. Some rabbis even rule that the wool combing must be done for the sake of the mitzvah.40 Before spinning the wool, one should say aloud, “This wool is being spun for tzitzis.” If a non-Jew spins the tzitzis there is a conflict of opinions on whether the tzitzis are kosher. According to the Shulchan Oruch HaRav, such tzitzis are not kosher.41 The length of the eight strings must be at least 12 ordinary thumb breadths (approximately 9 inches) after the coils and knots are made.42 One of the strings must be longer than the others so as to create the revolutions."

http://www.kosherspirit.com/Article.asp?Issue=22&Article=301