Do you have any gut feelings, or any empirical data, about this?
Suppose you had 25 to 50 Marble King Rainbows, 25 to 50 Vitro Conquerors, 25 to 50 West Virginia Swirls, 25 to 50 Peltier Rainbos, etc.
Would they sell better as a Marble King lot, a separate Vitro lot, a separate WV swirl lot, and so on ....
Or would they sell better as lots of 25 to 50 assorted vintage marbles with a variety of makers in each lot?
Would condition impact the decision of whether to sort or not?