IMHO it comes down to economics to calculate the possible amount of cues made by those guys.
Bushka - (59-75) 16 years 1200 total.. 75 a year... basically at 100 each $ 7500 a year building cues... is that possible? He co-owned a pool room or something like that... according to statistics 10,500 was the median income in the US in 1975. IMHO I think he was probably closer to 1500 cues-1700. His advantage was not very fancy cues, pre-made parts, titlist base cues, many plain cues.
I would say that for all the makers. Paradise has similar parameters, not many fancy, I see ALOT of plain cues, some fancy. (48-67 or 68) Good 20 years, many helpers.. I would say 2000/2500 cues is a reality. Many unmarked, probably thrown out over time.
ON all the guys, many broken cues. Its hard to really know, those who do know are on the wrong side of the flower bed.
JV