Unbeaten this season, the Dalakhani colt reappeared with a win in the London Gold Cup at Newbury before following up at York off a 10lb higher mark.
He then beat subsequent Group Three winner Frankuus in a Listed race at Hamilton last month.
Varian said: "He's in good shape. He's been progressive all year and we're looking forward to running him up in distance again.
"He's a very likeable horse. He's a good goer and he has a good attitude. He seems to be getting better and better.
"We've always thought he'd stay well and it was commendable he was winning competitive handicaps over a mile and a quarter.
"The race he won last time at Hamilton was just shy of a mile and a half and the further he went the better he looked - he needed the whole of that trip to wear down Frankuus.
"He looks like he'll get better when he runs over further. We've got the St Leger very much at the back of our minds but he's got to improve a fair bit still."
Standing in his way is Charlie Appleby's Frontiersman, second to Highland Reel in the Coronation Cup at Epsom and narrowly beaten by stablemate Hawkbill in a Group Two last time out.
Appleby said: "If he repeats either of his last two runs he's sure to go close.
"He's given me every indication that he's in the same sort of form. In fact, I've never had him better.
"His work has been good and the ground will be fine for him. I'm struggling to think of a negative, to be honest.
"He's won at Newbury before and if he brings his A-game then he's got to have a serious chance.
"I've got lots of respect for Roger's horse, though, as he looks a big improver."
Hugo Palmer runs Crimean Tatar and Wall Of Fire but both horses are on something of a retrieval mission.
The Newmarket handler told At The Races: "Crimean Tatar hated the bottomless ground at York and came back sick, so I think he's still very much a blank canvas, having run well in the John Porter.
"He hasn't run since May but he's been training great and I'm very happy with him.
"Wall Of Fire got an awful ride in Belmont and then went a bit flat when he came back so we left him alone.
"He's owned by Australians and his target is the Caulfield Cup and/or Mellbourne Cup so a third-place finish would be really important to help qualify.
"I was happy with his work this week so fingers crossed."
Irish interests are served by The Tartan Spartan, winner of a Listed race at Down Royal last time out for trainer Pat Shanahan.
The Brian Meehan-trained Agent Murphy won this race two years ago but must return from a lengthy absence.
John Gosden's To Eternity, the Mick Channon-trained Harlequeen and Horseplay from Andrew Balding's yard complete the field.