Best Offster Rockers for RPM

Ok for the sake of this discussion, let me revise my parameters. Let's discuss the best offset regardless of brand to improve the RPM head.
The goal is a steetable head that could go on a ~400cid engine and make 500lbft/500hp

pittsburghracer said

do you presently have rockers

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I have stock stamped rockers for BB and SB and a set of SB speedmaster stainless on the shelf. So essentially no, I have not purchased a set for this build.

pittsburghracer said

The pinnacle isn’t the problem, the last of available good volume is the problem.

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Referring to low lift flow I assume? Off topic, but If you had to prioritize either offsetting the pushrod or a bigger valve which would you go after?