In most cases pencil can be used to mark the set number under the base. I don't believe it will wear off soon unless moved around quite a bit. If it does fade just over write. Some bases are too irregular for script and do require stick-ons. I catalog my pieces by categories and do not put retail prices down as I feel they are worthless at best, and wil be misleading as to value for the uninitiated. Maybe you can make a separate list of some of the knowledgable people in this forum and elsewhere and instruct your executor to hire one of these people to value the pieces. For a significant collection I believe a fee will get the action one needs. Regarding sale, perhaps retaining an agent on a commission basis to sell the pieces will work. Somebody not familiar with ebay or other forms of sale, and not familiar with the pieces and their value, not familiar with potential buyers, and who is trustworthy needs to take charge. It will almosts be a necessity to maximize sales receipts.