leedy,How did you compute the retail value? Is that what you paid? eBay? Professional appraisal?
I have followed asking prices and actual selling prices on eBay for several years. I also account for rehabbing cost and labor for drums that have been cleaned up and restored. Rebuilt or rewrapped drums do not get the same estimates of value as do the rehabbed original equipment drums. I worked for 30 years as a manufacturer's representative in the music business which resulted in my being in hundreds of music stores over those years. I have seen, bought, sold, and traded for many of my drums and cymbals with the proprietors of many stores. For me, cymbals are more on a guess work basis from what I see online or in stores.
I try to be realistic about what it would cost to replace the item with a very similar one. I also use a "what might I pay for this if I really really really wanted it" criteria for the more unusual or rare items.