What is SDS PAGE gel polymerization time?
There is nothing like a general polymerization time, as this is a chemical reaction which depends on many factors. The most important are:

APS: Concentration and and the age of the chemical are important. APS decomposes over time when it is not stored completely dry (which it is not on most benches) and also with freezing thawing cycles in storage. APS provides the free radicals necessary for the reaction; without it no polymerization will happen. In my experience APS is the most critical part of the reaction, with old solutions making the polymerization really slow. I would make a stock solution, freeze it in aliquots. For making gels I thaw on aliquot and keep it in the fridge afterwards for a week and then discard it.

TEMED: Is the catalyst for the reaction, too much of it will start the reaction very fast. 

Temperature: The warmer it is, the faster the polymerization will be. In the cold room you will not get complete reaction, if any.

What you can do is to store the remaining acrylamide in the beaker and wait until it is polymerized. Then your gel should also be ok to use. A longer polymerization time (assuming that your gel was completely polymerized before) will not change the resolving capacity of your gel.