Plastigage is the defacto standard method, but it doesn't show runout, if it is present. This is an 'ovalling' of the hole(s) that, in this particular arrangement, would let the cam try to wiggle fore-and-aft in the oval-ed hole. The best way to measure that involves bore gages, not something many people have: if you want to be one of those folks you can get some Chinese-made ones for less that would be enough to do the measuring job - just don't trust them for fine work. While an oval-ed bearing situation isn't common in this engine, it is caused when the oil was run too long for too many times, or if high-detergent oils were used for an extended time. Both situations make for oil that lost its lubricity sufficiently to allow bearing loading to exceed safe limits, and then the aluminum alloy wears as the cam bearings get striations on them in the direction of rotation. It's pretty obvious to the naked eye when this happens, though, so fancy bearing tools aren't usually needed to find it.
The bearing clearance is best measured under the cam, not on top of it, with the cam chain loosened up so it doesn't add artificial loading to the Plastigage and make it spread too much for the actual torque on it. You can loosen the chain in-situ by releasing the cam chain tensioner bolt of the [rear] chain-slipper-adjuster, then while pressing the middle of the slipper toward the back of the bike, re-snug the bolt to hold the slack on the chain. Then you can estimate your clearances with Plastigage on the top sides of the cam bearings - all this so you don't have to disassemble the whole top end just to check for clearances.
