Play as many tables as you can, as it is freerolls, you will have to call an all-in sooner or later, and out of 10 tables you can be happy if you stay with one or two.
The point here is, when you are trained to watch 10 tables, you will be amused, how focused you will be on every chipsound, movement or anything that happens in one single tournament, that you are going to play later. From the handling point of view, I agree with two to 4 tables at once would be fine, but come on, how many play Poker there? It's bingo and it stays bingo, until you struggled out of the mug. The only decision is: Are my cards good enough to go all-in?