Yes, smaller board will help a lot.

Teaching the correct foot placement is essential - starting and once up on the board.

One of the hardest items is teaching them to flip the board when starting. This is resting their feet on the board, then pushing the board down with their heels to get in the correct position. Kids cannot do this with big boards. There is also a method they can use with holding the board up with their hand and holding the rope with the other.

Correct driving is also needed. Having the youngster on the side of the wake so they are not directly behind the boat. Tying the wake rope on the side of the tower. Going slow as you are starting when they are getting their feet and board in the correct position