Six years of 602/Sound Creation price tracking is available as a public database. Quick overview here:
http://black.net.nz/cym2011/pcalc2.pdf
I do special analysis on request, or you can have the raw data as a spreadsheet.
In brief, you only get the highest prices for cymbals in excellent condition with all logos strongly visible. But one would normally expect to pay closer to the average. Prices on eBay are highly variable week to week so I maintain you need a reasonable sample size to get stable estimates. If the cymbal sizes you seek aren't there that's because there weren't enough to get good estimates. In that case I often resort to just giving you all the raw data for a particular model and size.
Given that they are paper thins you might also want to check out a previous analysis I did which may help to isolate that effect. Lots of reading but then it is a complex topic:
http://www.cymbalholic.com/forums/showthread.php?30271-New-Paiste-602-SC-value-rule-of-thumb
Enjoy.
Your friendly retired statistician.