Hello,
Since we are discussing values w/r/t proof coins on this thread please allow me to suggest an alternate and distinct means to view encapsulated proof sets.
A while back I perused through both of the CherryPickers' Guides to Rare Die Varieties (5th Edition Volume I - 1/2 cents to
Jefferson nickels & 4th Edition Volume II - 1/2 dimes to modern dollars plus gold and commemoratives) to categorize the proof and mint set varieties that contained notable financial value over and above the commonly known denomination of the coin in question.
Also included in this assortment are those coins that I personally just enjoy viewing based upon singularity: not necessarily financial worth.
Should one decide to pursue this myriad of fascination, may I suggest investigating Appendix C: Proof Set Varieties on page 455 of the 4th Edition Volume II.
It is at this location where a convenient docket composed of a preponderance of significant varieties exposes any obsessed collector to an easy-to-refer-to one page summary of what to focus on for the proof sets initially invoked in this thread.
fyi,
mdpmedia