MindWare Keva Contraptions 50 Planks

Does the 200 plank set contain instructions for all the instructions in the 50 plank set?

How wide are the planks? Do only marbles fit on them or could it work with matchbox cars?

The age range says 7-11, but it looks fairly complex? Would an older child get bored quickly, or is there enough here for a preteen- young teen?

What is the measurement (width & length) of the individual keva plank?