Finally got a juke?! Sweet! What did you get?
I have a shitload of extra 60's - 80's 45rpm records if you're trying to add to your collection.
On my 3700/3800 jukeboxes I've been able to make one quick adjustment and easily play 2 records stacked on top of each other. I do this so I can stuff 2 A sides into one record slot instead of always having a crappy B side. I take a minor dab of hot glue and put it on both the inside side's label. They still easily come apart but hold together enough that the record doesn't slip on top of the other one.
I've been playing records on my 3700 for a few years double stacked back to back A sides and have not experienced any failures or problems because of it. I try to pair up the records so maybe a thicker one is with a skinnier one, but even with the added friction, weight and diameter of pulling two records out I have had no problems with the record or the jukebox mechanism. I can see how it would be extra wear and tear on it since its not a human muscle getting stronger with use but an acceptable risk on my part and so far I have noticed zero problems with anything in the system with constant use.