I don't understand why you do not have confidence in the cam grinders recommended clearance. It is established as part of the cam design, depending on ramp profile, seat time, wear characteristics of camhaft and valvetrain materials, expansion factors, etc. It is certainly a safe starting point. There is always going to be noise with a solid lifter engine. Tighten up to reduce the noise, and you risk burning valves and/or wearing out the cam. Too loose and you will have a power loss because the valves aren't doing what the camshaft is telling them to. Any possible "preferences" that folks may have can be due to differences in their feeler gauges.
