The distance between pickup and string is a very important factor for output and sound.
As a general rule for the bridge pickup - put a nickel on top of the pickup under the high E string and play the highest note on that string. Adjust the height on that side of the pickup till the string touches the nickel. Repeat the same with the low E string, but use two nickels on top of each other. If this gives you too much output, you can reduce the height slightly. Don't forget that twice the distance will reduce the output by about 60%, and the sound will lose some lows. NOW, you can adjust the neck pickup to match the output of the bridge pickup. For the sound test, use stage volume.
Height Adjustment for Steel Guitars:
A good starting point for pickup height adjustment:
Start with 1/8th" spacing at the high strings and 3/16th" spacing at the low strings, and then you can raise or lower the pickup accordingly, depending on the instrument, your style of playing, etc. - until it sounds right to your ears.