The remarkable 10-year-old has contested the last four renewals of the Champion Hurdle, finishing a luckless third in 2014, fifth in 2015, fourth in 2016 and fifth again 12 months ago.
He has stuck to the tried-and-tested two-mile route so far this season, most recently claiming his fourth victory in the Champion Hurdle Trial at Haydock, but will step up in distance on his return to Prestbury Park next month and Twiston-Davies admits only time will tell if his stamina will last out.
Speaking at a media morning at his Naunton base on Thursday, the trainer said: "I'm not confident at all (about the trip), that's why we're going to hang on to him a bit and the plan is to ride him differently.
"We won't be making all the running and doing things like that. He's won over two and a half quite a few times, but has he been staying on at the end? I don't really know.
"If he can improve for the distance, and people tell me he will, I'm sure he'll be all right.
"We will ride him that bit differently and I can see him galloping up the hill.
"Sam (Twiston-Davies) has been keen to try three miles for a long time."
Despite getting on in years at the age of 10, Twiston-Davies is adamant his long-time stable star remains at the peak of his powers.
He added: "If you look at his races this season, he's probably the best he's ever been. I think he really has been incredible this year.
"It would be great if he won it as he's the horse of a lifetime."
The New One has not even been entered for the Unibet Champion Hurdle this year.
Connections still have the option of stumping up the £20,000 supplementary fee, but Twiston-Davies insists it will not even be considered unless defending champion Buveur D'Air misses out.
"It was so sad The New One's first Champion Hurdle was taken away from him as he was knocked out of it," Twiston-Davies continued.
"Unless Buveur D'Air does something funny, we have made our minds up to try something different.
"It was easy enough to make this decision when Buveur D'Air gave him a good beating at Kempton in the Christmas Hurdle, and the Irish are looking strong in there as well.
"Next season he'll go back to two miles again, whether he wins the Stayers' Hurdle or not, as that's where the money is."
The New One will be joined in the Stayers' Hurdle by stable companion Wholestone.
The seven-year-old opened his account for the campaign in the Relkeel Hurdle at Cheltenham on New Year's Day before finishing second to Agrapart on his return to the track late last month.
Twiston-Davies said: "He's done well all season and loves Cheltenham. He just got slightly outstayed in that very heavy ground last time. It won't be like that this time and I'm sure he'll get home.
"His course form is really good and he ran really well to finish third in the Albert Bartlett last year."
Other leading Festival hopes for the locally-based trainer include Ballyoptic and Calett Mad.
Ballyoptic earned himself a shot at the RSA Insurance Novices' Chase by winning the Towton at Wetherby earlier this month.
"He's got much the same sort of profile going into the race as Blaklion when he won the RSA," said Twiston-Davies.
"It was a very good run at Wetherby. He was very good and he did everything right. Having had a disappointing run at Kempton, he came back with a vengeance.
"In the early days hurdling, he did well on good ground."
Calett Mad was disappointing in a Ballymore Novices' Hurdle trial at Cheltenham in November and flopped again in the River Don at Doncaster.
However, he showed his true colours when landing a Pertemps qualifier at Musselburgh last time out.
"I would have thought he'll go for the Albert Bartlett," said the trainer.
"He was disappointing in the River Don. He just got worn out and was well beaten.
"I didn't want to run him again quickly, but Anthony Bromley (racing manager for owners Simon Munir and Isaac Souede) said we should get him qualified for the Pertemps Final.
"We just rode him totally differently at Musselburgh, to run on and try to get a place really, and it really suited him and he romped home.
"We'll hold him up again at Cheltenham as that was what brought about the transformation."
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