What is more accurate , the fozgometer or the diplay of the oscilloscoop

Doing it by ear sounds like a good idea, but I would only do it as a last resort. First, it requires a fair amount of experience and practice to get good at it. Its far easier and faster for someone who's never done it before to just use a DMM. As long as the DMM is a quality unit, it will be more accurate than going by ear. There's no guesswork involved. When you're done, you know its right.

There's other factors to consider as well. The article you reference talks about tuning the room to compensate for the azimuth being off. Again, at first glance it sounds like a good idea, but its not. When room tuning is brought up, the first thing you usually think about is tuning the room vs eq/processing. There's a downside to using an eq because you're fooling with the signal in ways that can have a big effect on SQ. There's no downside to adjusting the azimuth directly. If its off, adjusting it will always be a positive thing. If you choose to leave the azimuth alone and use an indirect method of adjustment, you now have 2 problems. First, if the azimuth is off due to the stylus not being perpendicular to the top of the cart body, you still have the crosstalk. Fooling with external factors to get a center image can't eliminate the crosstalk, so its only a partial fix. Second, what do you do if you have more than one source? If you play a CD, now that's going to be off because you made proprietary adjustments meant for your TT only. When you make changes to your room, they apply to all sources, not just one.