Rick....while I agree selling a collection, a piece at a time retail is the way to get the absolute top dollar, it is far more time & effort than simply having it auctioned off. Most times, the "homeruns" will offset the "dogs" to a point where you will get close to retail for everything.
Also, as far as fees go, I'm not sure how it's done everywhere else, but I charge a flat 10% and that includes everything. I picked up collections in California, Illinois, Cincinatti, & St. Louis this year for my sale. I mailed out 20,000 color brochures, rented a facility, hired a staff, hired an auctioneer, the whole bit for the flat 10%.
Case in point, in '06 when we sold all of the good globes. I asked the consignor what his hopes were, and he said $100K was his worst cast scenario, $150K was his dream and $125K was what he figured he'd net. After it was all said and done, I sold his 80 globes for $148K gross, and charged him $14,800 in commission, netting him $133,200. He was happy, I was happy. I showed up and his house one day and picked up every globe and then a few months later handed him a check. No fuss, No mess.
I'm not trying to convince anyone, it sounds like this fella is going to do just fine sellig his stuff, just wanted to articulate that an auction isn't nearly as expensive as some think and is pretty painless on the seller.