hi I have just finished putting a wiring kit and a set of seymore Duncan alicino pick ups in my les Paul I'm not sure how far to set up the pick ups from the strings
Play the low and high e strings at the same time and adjust the height until they have a balanced output volume.
Play with the height until you like the sound. In my experience, the closer the pickup is to the strings, the louder it will be, but also the more distorted it will be. You can play with this to get a good balance of high and low. My Epi Les Paul 100 sounded awful from the factory. It was incredibly muddy, but by adjusting the bass side farther from the strings and the treble side closer to the strings, I made it sound a million times better.
If you have set the action height already, consider that most people who play a low action, set the Low E, slightly higher to prevent buzzing (it's a fat string), so if you haven't done that, do it first, then adjust the pickup accordingly.
as long as the volume is balanced your ok. i like to set the bridge that little bit closer so i can switch to a cutting lead break.