You didn't say, but I think your Wright has a capscrew on the blade, screwed into the spindle, right? For those of us who have through-bolts, we use two wrenches, one on the top, the other on the bottom. Apparently, you needed to hold the blade, while turning the capscrew. I service some lawn tractors for home-owners, and they typically have capscrews (e.g. John Deere). The procedure scares me. I too use a Vice-Grip to hold the blade, blocked up against the deck someplace. But, it is subject to slipping off. There must be a better way. If I had to deal with capscrew arrangements regularly, I would try something different.
When changing bladles on my 21" mowers, I block the blade with my foot on taking it off. When remounting, the dull side of the blade can be held with the second hand.