Hi Again
I personally would try the vent doll with all ages.
It's not what you use that determines wether the chidren will like it or not but wether the routine is funny enough at their level.
I currently have a gorgeous dog from "Practical Magic" and often get shouts of "Its your Hand" for the first few seconds but this is soon forgotten in hounds (pun intended
)of laughter when he starts cleaning himself in the way dogs do then licks my face.After that I have them hooked.
Kids just love toilet humour
Children are only the hardest audience to play too for those not experienced enough to handle different situations.
Make the magic fun and interesting with the emphasis on "fun" and the children will not look for the mistakes or how it works as they are too busy enjoying the show.
Try and baffle them with the clever stuff and they'll make your life hell.
If you're finding children hard work or uncontrollable then i suggest you go back to the drawing board or try another line of work and leave it to the proffesionals.