In the SON-R test that DD will do there is a task with puzzles where she has to do them but without example or knowing a priori what the picture looks like.
I was curious how many pieces could DD 4.5 do so I got some new puzzles, un-do them and put away the box with the drawings. DD did the 16-pieces without any difficulty. I am going to buy other puzzles with more pieces and see how far we get.
I am curious, how many pieces can your DCs do? - remember, without having a clue of what the final picute looks like.