My 18 month son has just started to show interest in toileting, so I'm in the market for a seat. He's very short, so regular toilet seat inserts are out -- too high off the ground! Has anybody used the Sesame Street 2-Way Learning Potty? It has a removeable bowl & a big splash guard. Elmo picture is a definite incentive for the kiddo. Have you found this one to be especially messy or difficult for kids to climb over the guard/deflector? Thanks!