Pat has it right, just don't pour your "mush" too concentrated or you will have seedlings sprouting as thick as hair on a dog and hard to separate to replant. I used to repot the seedlings shortly after they sprouted in gallon pots. I would let them grow for a year and cull any that exhibited the characteristics of a twisted, dogleg tree, only kept the straight trunk ones.
I gave away all but a few of my year old seedlings. Some had good luck growing them, others did not.