I have found those OM Ortofons to be a pain as well.
Nowadays when I align a cartridge, I don't look from the top so much anymore. I do most of my 'viewing' from just above the surface of the record in front of the cartridge, looking straight down the chute of the cantilever/needle while shining a pen flashlight down the chute as well. To get the stylus on the crosshair, I line it up first looking from the front, and then from the side since the diamond is always slightly back from the tip, and often tilts a bit forward, so I try to make sure the actual tip is on the crosshair. This is more taxing on my knees and back than my eyes :)
I start with the cartridge all the way in the front of the headshell, squarely in the front of the headshell slots. I start with the outer null point. Sometimes I get lucky, and it is perfectly aligned at that point. If it's not square, the cantilever will almost always be pointing towards the edge of the platter. If that's the case, I will start moving the cartridge backwards evenly a mm or so at a time, re-checking each time on the grid. Again, first get the stylus on the crosshair, and then check for alignment of the cantilever on the gird, looking at record level from the front with a pen light. I also shine the light from the back as well, and check the silhouette of the cantilever on the grid, with the light shining from the rear. Notice I'm looking for cantilever alignment, and not cartridge body alignment.
Anyway, once I get aligned on the outer grid, I of course move to the inner grid. Many times the inner grid is good-to-go, but if not, I only do very small tweaks at that point. The tweak might be a slight twist in the headshell, or further moving backwards. Make sure to check the outer grid again once the inner grid looks good. The inner grid is most important...if you have to choose between the two.
BTW, that is for Baerwald alignment, which is what that Lab-440 arm is set up for.