Update: I have been riding it some, about 80 miles total. Each time I park it, it marks its spot with a few drops of oil. Had no drips prior to having the clutch replaced by dealer. Finally thought it could be time to check oil level. It showed over full on side stand, stick screwed out. Dealer did change oil. Aha! Tied bike up straight, and began to remove oil with syringe and tubing, removed about 80 to 90 cc to get level down to top mark. Guessing they dumped in an entire quart,

My question is: could the overfill cause my drips? Could not really see any oil in transmission breather tube.

Check to see if the oil drain plug is tight.

It is neither damp, nor oily. It is dry as surrounding area of cases. Oil seems to be coming from high on the rear of engine. However, I will check it. Thanks.

The transmission breather tube exits over the rear of the engine.  Is it coming from there?

An overfill could certainly cause it to overspill the breather because more oil is getting flung around and therefore more oil mist is created inside the tranny case.  It could then coalesce into drips within the breather tube.

I will bet any money that the techie who overfilled your oil drained it on its sidestand.  That will not drain the transmission fully.  If he then dumped in the specified amount of oil and did not bother to check it on the stick.  Voila. One overfilled transmission.

If a clutch is slipping, the very first thing to check, esp after a long lay up is that the cable is not binding and the actuator is not partially seized or misadjusted.  At 350 miles, it is very unlikely to be faulty clutch plates (unless the clutch cable was binding or misadjusted previously  ).

Even a cable that feels free off the bike can bind up internally under pressure. 
The only time I have ever encountered organic clutch friction discs going bad over time is when they have suffered water contamination.

Got the bike up on the lift table. Oil drain plug was tight. Apparently not leaking. Checked breather tube, but no sign of liquid/ oil. Overflow autolube tube did have some oil drips. Checked tank level, not completely full. Used my finger to find the opening to the overflow. Oil level was a little higher than it. Drew about 20cc to get it below. Cleaned off all oil from engine that I could with shop towels. Took it for about a 20 minute ride.; various speeds and gears in 98f heat. Parked it with white shop towel underneath. 5 hours later and no drips.

Thanks to all for help and advice! Try to read all the posts on a daily basis. There is so much knowledge available here.