Hello,
I see you got tons of Info already to build your own criteria that will work best for you,
The way I do it is placing the seeds into a cup filled with water along with a lid or anything that will block light for 24 hours, after those 24 hours you will see them sinking if you gently stir the water, this means that the seeds absorbed all the water they need in order to start the germination process, depending on the condition of the seeds some will germinate within this first method (you will see a tiny white protuberance (hypocotyl) popping out)- After those 24 hours on water, I get a better germination (IMO) if I place the seeds on a wet paper towel (not soaking wet), very soon (1 more day or so, again, it depends on many factors including its genetics) the remaining seeds will start germinating, i never wait till the little root (hypocotyl) starts gowing before I place them in the growing medium because this first boost is responsable for the proper growing of the young stem that will subsecuently emerge from the seed.
At the end, the best thing you can do is experiment, purchase some mexican brick weed and practice with the tons of seeds you can find in there, you will also get to see a bunch of different stages and conditions of the seeds-
Seeds are intelligent, if you are having problems with germination, Its more likely that you are not gathering the proper conditions for a seed to germinate- as long as you have water, oxigen and a normal temp (I also avoid light on the first 24, this makes them think they are underground, and when they are in the paper towel or growing media let indirect light because some seeds (not sure if cannabis seeds but what the hell) also like or need the proper light freq. in order to germinate) they will know what to do...
Good luck and have fun!
*Sorry for any grammar / spelling error, English is not my native language*