As far as I'm concerned, the only reason that anyone should switch to roller rockers, is to maintain correct valvetrain geometry. And, with that, you need adjustables. There is very little actual testing out there on this. I believe ZZP did some testing way back in the day, but documentation is limited.
I was looking at running an ST5 cam, but I was wanting to switch to T&D shaft mount roller rockers. I was told they were 1.7 ratio, but when I recieved the rockers, they are only stamped with 1.6. So, as of now, ZZP is creating a custom cam with more lift to make up for it, but with the same duration. I may measure the difference in lift between stock rockers and roller 1.6's to see what the actual difference is, if it's not too difficult. I need to look at my heads first to see if it's possible anymore.
I care very little about peak lift numbers, or peak power numbers for that matter. Your engine spends very little time in this area during a 1/4 mile pass. You are way better off working to increase airflow at lower lifts where your engine spends much more time. (And power across the band, instead of peak.)