I always thought that Blue Diamond was as fast as any of the pointers he ran against. Of course, he may have had a little of that blood back a generation or three. Dunno if any of his blood is still around; if anybody knows, George Tracy probably does.
Blue Diamond's career was cut short by Lyme Disease but there were many rumors about him. One man told me that George Tracy had ruined him and even George wouldn't breed to him because he was so soft. That of course was TOTAL BS and I told the guy so. I was living in the Shenandoah Valley at the time and in the summer I was in Glenville almost every week so I had a pretty good handle on the whole Tracy string.
BTW, imo the two best Setters I ever saw were Blue Diamond and Mr. Thor who I saw many times at Killdeer when I was teaching at Ohio State. And for you Setter guys that think I'm strictly a Pointer guy, I started in Setters with a son of Flaming Star out of Harry McIntyre's old pie bitch M's Blue Heather. He was Heather's Star Bandit. Long story short, he jumped a deer; the deer made it across the highway, Bandit didn't. I cried like a baby over that. I had bought him as an 8 week old puppy and raised him in the house. I never let myself get that close to another bird dog.
Then Gene Uhlman turned pro and sold me Countercharge and Counterdrive, both RU Chs with almost 200 wins between them and the rest is history. For years, I got a placement almost every week, often two or three in open and amateur shtg. dog stakes. When I retired Charge, he was the top winning male with some 115 wins. (IIRC, second iirc to a bitch with over 120.) Drive had around 75 all shooting dog or all age (no puppy or derby).