Idling during warm up the noise can diminish and almost cut out for a few seconds as the ECU transitions between engine operating strategies. Another way to tell that it isn't the valve train, is to rev the engine to a high RPM and cut the ignition. (<-- Do NOT do that on a turbo engine.) On previous vehicle, I drove on a hydraulic roller lifter that had a bad roller. (lost some bearings on one side) The roller flat-spotted and pitted the cam. That did not take long! That kind of mechanical noise is distinctly different. So is the valve clatter you briefly get after an oil change; or lengthy sit. (avoid the clatter by flooring the accelerator, before beginning and during the crank) If you really are getting valve train noise, then something is wrong... and the damage should be measurable if not immediately apparent upon disassembly.
With regard to oil weight, as a general rule, noise on startup means go lower on the first number. Noise after warm up means go higher on the second number. Even though the same numbers on everybody's bottles, oil feel/thickness/viscosity seems to vary between brand and type (mineral/part-synth/full-synth). So some experimentation may be needed in order to find the happy medium for your brand/type/engine/comfort-level. You can mix weights... half 5W and 10W for instance.