The acetone will flash much quicker.... BUT you better have an oxygen tank slapped on your back to avoid breathing the fumes. And don't have any open source flames where you are putting that acetone laced vapor into the air.

The main flaw I would suspect with the paint flashing too quickly is that it is not going to allow the paint the time to naturally self level.

And acetone is pretty nasty stuff all round. Acetone can eat into plastics, remove enamels, cleans hardened nail polish etc. So based on acetones nasty ability to eat things prior to it evaporating and drying, my biggest fear would be that when the second coat is sprayed the acetone will spend half of its energy trying to eat the paint layer below and the other half of its energy evaporating. IF it is able to eat or soften the lower layer of hardened paint, I suspect you would get a bad case of orange peel or elephant skin

But most importantly keep the health reason in the back of your mind if you plan to experiment with acetone...
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