You can use Plastigage (the thick stuff) to check the clearances. You want them to be within 0.0012" from best to worst (difference) or else it will vibrate a little until the smallest clearance one(s) wears in. If you think about their alignment, you'll figure that part out...
On these Fours, the center two cam bearings always wear the fastest and deepest, despite the fact they get the most oil. This is because the cam chain pulls downward at low engine speeds, due to the tension, and at higher speeds the center of the cam flexes toward the front of the engine a little. You'll usually find the wear pattern "leans" toward the front a little on the inner two.
I have sometimes taken the cam bearings and swapped their position in a given engine if the centers were worn past the 0.008" limit, but the outers were less. If the bike is not intended for lots of 7500+ RPM use, it works fine for daily-driver and touring use. It extends the life of used cam bearings by about 20k-25k miles or more. Synthetic oil will help a lot, too: I just saw where Mobil 1 if finally available in 20w50: I can't wait to try it. I like their 15w50, but it is a bit light for significantly worn engines, losing a little of that helpful cushioning effect.
In my book I recommend the bearings be installed back where they came from: this presumes, though, that the clearances are still below the wear limits. Excessive wear calls for excessive measures.
