Normally it's 24 hours at room temp, then you start the post cure at elevated temperature. Some time ago I downloaded the full spec sheets from the MGS website. They list the curing schedule as 24h at room temp, followed by 15h at 140°F. They also give a figure showing Tg as a function of post cure time (and temp). The largest improvement is between zero and 5 hours, but the Tg really levels off after 15 hours.

http://www.mgs-online.com/

Go to "technical information" and look in the "registered laminating resin systems" folder. The spec sheet for L285 is in there as a pdf.