For reliable navigational information the approximate coverage of a 3° glideslope is:
1.35° to 5.25° from the horizontal and 8° either side of the localiser.
0.45° from the horizontal to 1.75° above the glidepath and 8° either side of the localiser.
0.7° above and below the glidepath and 8° either side of the localiser.
3° above and below the glidepath and 10° either side of the localiser.