As you have the facility to alter the Rockwell, I'd suggest that you try it and set it up to suit you best by experiment.
Go for a midpoint 3 to start, and then, if that's not right, try either side.
My own view is that trying to equate or yardstick one razor to another isn't helpful. All the factors change; weight, blade used, handle length, head geometry, blade gap and so forth. It's mostly a chalk and cheese exercise.
You can alter it to get what you want. In fact, I'd forget about trying to match to another razor and just try combinations until you find the best set-up for you.
And then be ready to experiment some more when you change blade brands and types.