Firstly, check your gauges. Swap the one with the higher reading with one of the others as see if you get the same reading. If not the gauge is out of calibration or naff. Many on the cheaper gauges can't be calibrated, in which case, as long as it reads the same constantly, you just deduct the error.
Once you've sorted the above out, balance 1&2 then 3&4 then bring 1/2 & 3/4 in balance by adjusting the middle
Once you've sorted the above out, balance 1&2 then 3&4 then bring 1/2 & 3/4 in balance by adjusting the middle
Later