The trainer said on Monday he would watch this Saturday's Tingle Creek at Sandown and then decide on the nine-year-old's next target.
A step up to three miles for the Christmas showpiece has long been mooted for the dual Champion Chase winner, but after his first defeat in four and a half years at Ascot, when he was stepped up to two miles five furlongs for the first time, his camp are considering their options.
Cyrname , who beat Altior by a comfortable two and a quarter lengths and is currently the joint-highest rated chaser in training, is the 5-2 joint-favourite for the King George at Kempton along with Betfair Chase winner Lostintranslation. Last year's winner Clan Des Obeaux, a best-priced 11-2, is also shorter in the betting than Henderson's stable star.
With potentially fewer sharks circling in the division he vacated – and most of the major contenders for the two-mile crown in action in Sandown's Betfair-sponsored Grade 1 – the five-time champion trainer is keen to see how the likes of Defi Du Seuil, Un De Sceaux, Politologue and Sceau Royal get on against his own Janika.
Since his defeat at Ascot, Altior has headed the Champion Chase betting at a best-priced 7-2, with the Willie Mullins-trained Chacun Pour Soi the only other runner shorter in the market than Tingle Creek favourite Defi Du Seuil.
"He's all well, although I'd not say he's all well for the King George as we haven't really decided yet," Henderson told the Racing Post on Monday.
"It will be interesting to see what happens to all these two milers on Saturday [in the Tingle Creek]. They're the best around apart from him, so we'll see how they get on and then decide which way we're going to go."
Should Altior revert to two miles Henderson will still be well represented in the staying division with Santini, whom he revealed had returned to work after a breathing op, and four-time Grade 1 winner Might Bite, who will have his first start of the season this weekend.
"Might Bite 's in at Aintree and Huntingdon, but I think the Many Clouds Chase at Aintree will suit him well and then Top Notch can go to the Peterborough," he said. "Santini is just back cantering after having his soft palate cauterised. He's back in action again so we'll form a plan with him."
Henderson knows staying chases will eventually be Champ's game, but he is in no rush to step Friday's Newbury winner up in trip.
"There were a few dramas along the way, with loose horses and thinking he'd jump the water again because he enjoyed it," joked Henderson of the seven-year-old's eventful victory during which he nearly unseated Barry Geraghty on the first circuit and then threatened to take the wrong course on the run-in.
"I was delighted with him, he wants three miles but there's no rush to go that far. The plan is the Dipper at Cheltenham on New Year's Day."
Ok Corral disappointed in the Ladbrokes Trophy having headed the ante-post market all week, and Henderson said: "He's fine, he just raced a bit too keenly. I think he wants an easier three miles and dropping in a bit more. He was doing too much."