There is always a risk when dealing with a private party and usually the risk increases as your asking price increases. When I've rented properties in the past, I always thought it wise to rent slightly below market and reduce the risks.
I'd recommend that you determine the typical sales price for your lens, then knock 10% off of that and offer to include PayPal fees and shipping. You'll have offers from numerous buyers and there will certainly be one or two that are just as reliable as Adorama. True, it might take you a few minutes to weed through the candidates but you should be able to do an easy, clean deal and make quite a bit more than Adorama would give you.
I hope I have the chance to weed through candidates 
I guess I can keep it on CL for a couple of weeks and then take my chances here...
