If the net ratio ends up at only 1.56, then yes....... the spring load requirement would be lower.

Is the .568 number “net lift” with full spring load after lash?

For a 1.55-ish net ratio, you should be okay with springs that are 145-150-ish/380-400(at net full lift), and trying to keep the open height so it’s within .100 or so from coil bind.

The only personal experience I’ve had with beehives on the dyno are BBC marine applications, where they haven’t shown any magic to me thus far.
I’ve sold quite a few, but my own testing with them is pretty limited.

“In theory”, they should work in your application.

Going strictly off the specs, something like a Comp 929 set up at 1.870IH should do the trick(150 seat/390@.550 lift).