The lightly-raced six-year-old is a 13-2 shot for the race after landing the Grade Two Osborne House Relkeel Hurdle at Cheltenham last month.
That was over 2m5f, his longest trip to date, and O'Neill is weighing up whether the three-mile trip will suit the horse.
More Of That, unbeaten in all four starts to date, would go up against four-time World Hurdle winner Big Buck's and 13-2 shot At Fishers Cross, who McCoy may ride instead.
But O'Neill, who has teamed up with the 18-time Champion Jockey to great success over the years, would love to see McCoy opt for his entry instead.
"I would imagine AP will ride At Fishers Cross but he will come to ride work this week and next week and make his mind up," said the trainer. "I hope he rides ours.
"Do I have a doubt in my mind? Well, I think he will stay, though going to Cheltenham for the festival is a hard thing to do, they don't hang around and the finish is up a hill. We don't really know.
"I am not totally sure he will go for the World Hurdle, it makes me nervous that he has not raced over three miles before. It is going into the unknown."
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