From my limited experience, the trouble with cards that don't often come to market, ASSUMING they are scarce, rare, and desirable, distills to forcing yourself to be patient finding the right buyer who desperately wants the item.
Quoting from NEVER CHEAPER BY THE DOZEN, page 428:
"Bill Mastro said something that's appropriate here - "It's like so many things in the hobby; maybe 99 percent isn't worth a lot of money, but the 1 percent that is, is overlooked. ... And people need to understand how to find the 1 percent." (6) As I intimated , much of the material I shared is not generally known, even if bits of it have appeared in auction catalogs. Adding these vital pieces of the puzzle [through reading Never Cheaper By the Dozen] now provides you with a much clearer picture of the lure and magic of these once 'free prizes'. Had you not know anything about regionals, nor understood the undercurrent fascination behind them, you'd be apt to overlook them, or ignorantly relegate them as oddball or much less important than mainstream issues."
Just some food for thought.
Cheers. --- Brian Powell