Anyone use speed master roller rockers?

I have some for a BBC that I haven't used yet. Got them as part of an unbelievable black Friday deal. I'm gonna give them a shot on a mild grind solid flat, around 550 lift. I don't think I would trust them over .600
Edit. Gonna have to run Hughes rockers on my victors. Not looking forward to that bill. Wish I could run PRW stainless.