I tried O-rings, lubing, tightening the pins, and none of those solutions worked for me. Then, one day when I was riding shotgun, I put my hand on the right latch handle and I could feel the handle clicking in time with the noise. You might try that because you can easily check the driver's side, and get a passenger to check their side. What I did then was to remove the latch handles, clean and lube all friction surfaces with SuperLube, and then reassemble. This included a thin layer on the outer surface of the washers with the 'fingers' on them.
You don't need to remove the roof to do this, and the whole job is maybe 15 minutes. You do need a #40 Torx bit for the machine screws that hold the latches in place, and a 3/8 or 1/2 ratchet. Just unscrew the screws, and the handle, thin washer, and screw will drop right out.
Don't lose the thin washer! My thin washers were completely flat - the pic shows spring washers, so I'm not sure if there was a design change. The screws had a small amount of Blue Loctite applied from the factory, but I just used a couple of winds of Teflon tape to make sure the screws didn't back out. Not sure what the torque settings are supposed to be, so I snugged them up, but not excessively. I did leave the extra O-rings in place, so they may be part of the solution. However, if the O-ring solution works for you, keep a few extra around, because they tend to fall off when you remove the roof. The e-clip solution only works for the early version of the latch handle that had rollers, if it works at all.
Here is a pretty good discussion on the 'other' forum:
As a final note, I've probably driven 16,000 Km in the 1 1/2 years since I did this and over some pretty rough roads in temps from 4C to 38C, had the roof on and off numerous times, and it's been absolutely quiet.