That sounds great, It's my first time growing these TD's. I have some other auto's that are finishing now. These are much more aggressive growers. It will be interesting to see how yours progress. I'm new at hydro, normally been doing soil. There is definately a learning curve but I gotta say I think it is going to be the way I grow pretty much from now on. There is alot to it, but a lot less guessing. Read a meter and adjust accordingly.
Wish you the best with your grow. If I can help I certainly will.
Are you running all 21 at once? You got some work ahead of you!!
Just soak like you normally do, when they sink you can put them right in the paper towel or wait till you see them crack really well. Doesn't matter.
Just dampen a paper towel and squeeze it out so its not soaked. I fold it up in 1/4 and put the beans inside the flap. Throw that in a zip lock and close it and put in cabinet that is warm. I put mine above the microwave. I bet you will have tails in 12 hours.
I'm not sure if you have seen FD's guide to autoflowers, but if not check it out. I just remembered you were talking about soil and you might want to try his terrace method, so you don't disturb the roots. I frigged up my first auto grow in soil cause I transplanted 3-4 times = No No with auto's.