There’s a school of thought that the edge will have damaged/fatigued metal if overheated during sharpening eg factory belt sanding. Until it is removed, there will be continuing problems. Flattening the edge before sharpening helps to remove the bad metal.
In my opinion, use a very fine grit. You’re only removing marker to see where you are hitting the bevel. I typically use my ceramics. My finest diamond is 1000. No need to introduce a deep groove when trying to find the sweet spot.
Richard is likely referring to a pair of “pliers “ made by the company you found on line. Maybe these, to help get a grip on the screws. Other members came up with modifications for tightening.