I have a roughly similar number of beams on my miner, but each beam consists of 100 salvage modules and 100 cannon modules. It forms a cylinder 200 blocks long and ~30 blocks in diameter. (My server has an enforced limit of no more than 700 salvage beams active at any one time per player.) It is 100 block length lines in a checkerboard pattern switching between salvage and cannon modules, and behind that the mirror of that checkerboard again in salvage and cannon, all attached to the same computers. One beam array.
This represents the maximum possible beam strength. More than that and you are simply pouring excess 'damage' onto already mined blocks. (Some have reported the maximum effective line being 91 blocks, but this may be due to a bug, it may not be correct, and even if it is correct, the bug may get fixed one day and I want to not have to then fix my ship.) For constant fire, the salvage beams are paired, one for one, with cannon modules. There is some evidence that mining may be faster using solely two sets of salvage beams and alternating between them. If true however, it is likely only true for smaller modules sets.
As MrFurb said, mining effectively is half the trick. I made my mining array into a cylinder, the beam is circular. This because I don't want square edges firing needlessly into space when I am mining edges, circles are vastly less wasteful of their beams than squares versus irregular shapes. I have a camera mounted above the beam array so I can see the beam beneath. I line up the top of the beam with the top of the asteroid, so the topmost beams are eating the topmost of the asteroid. As I cannot effectively see the bottom of the beam due to the density of the beams, I simply don't concern myself with what is happening at the bottom. By the time I've eaten the top, the bottom is if not eaten, almost so, and I will find out soon enough as I move the beam to the section uneaten.
I have also learned that jump is your friend when mining. I like being able to maneuver effectively so my battleminer has a two to one thrust to mass ratio. Despite this, the thing still moves like a slugboat. I also fortunately don't like waiting for jump recharges and have nearly 15% of my mass in jump modules. This means I can recharge my jump in 12 seconds. I can live with twelve seconds. I have found that traveling to the next set of asteroids with thrusters is both time consuming and frustrating. However eyeballing the sector coordinates, opening the map, moving the sector highlight to the correct sector (wasd keys) and then plotting a jump, gets me there 'much' faster. Once I learned that trick, I realized I could up my rotation ('R' on a thruster) to a full 75% and feel substantially less pain.
Now when I am mining, I spend substantially more time digesting asteroids than I do moving towards and aiming at them. The time I do spend mining I have maximum strength, maximum coverage mining beams.