The only Polytrack feature calendared this season, the Group 3 Merlion Trophy (1200m) on November 27, would be right up the street of a horse who scored five of his eight wins on the alternative surface, but Gray said he'd be happy to skirt around the weight-for-age event if the next runs showed he was not that way inclined.
The Kiwi handler would rather play it by ear instead of locking in any specific short-term target, though he remained convinced the Indonesian-owned Mossman five-year-old is Group race material.
"There are a couple of races I will look at for him until the end of the year, including the Merlion Trophy," said Gray.
"I've got a few options. There is a 1200m (Class 1) race two weeks before (November 14), so he doesn't have to run in the Merlion Trophy as it's a weight-for-age race.
"I'd rather he runs in a handicap. He's had a few cracks in weight-for-age Group races, but I'm sure he'll wear a purple saddlecloth (worn by Group-winning horses at trackwork at Kranji) one day.
"There's another Open (Class 1) 1400m two weeks from now (October 2). He could run in that race, too.
"Whatever he does this Saturday, he'll improve a lot from the run."
Gray said that the break has done Kharisma a power of good after a hectic campaign that comprised two Group race assaults (best result was a third to Mr Malek in the Group 2 Stewards' Cup over a mile), but cautioned he might not be fully wound up at his very first race back.
"I gave him a freshen-up as he's had a pretty busy campaign," he said.
"He's fresh and bright, but he's put on a bit of weight. I think he may be vulnerable first-up, there's still a lot of improvement left in him."
The horse Gray fears the most is Kharisma's runner-up at his last-start win in a similar Kranji Stakes A race over 1200m (turf) on August 1, Grand Koonta who was then fresh-up from a two-month spell.
Being also run on the Short Course, Saturday's race is shaping up as a rematch where Gray fears the tables may get turned this time.
"James' (Peters) horse will be hard to beat. Maybe he needed the run first-up," he said.
"The boy (Iskandar Rosman) did a good job. I think he outrode Vlad (Duric) by keeping him in a pocket and skipped away.
"Anyway, I don't think he would have passed us, but it could be a different story tomorrow. Danny Beasley (Grand Koonta's new partner) is riding as good as any jockey at the moment and I'm sure he'll give James' horse a great ride.
"I'm using the same boy, he'll get the same weight relief (three kilos). My horse is well placed and handicapped tomorrow, we'll use the weight to our advantage.
"There are some horses who carry a lighter weight than us (namely a five-horse strong team from Mark Walker), so we must respect them, too.
"But Kharisma is very good on Polytrack and it's a nice trip for him. He never runs a bad race, he's tough, and he has matured into a good horse."
When asked if the inside draw might not be the recipe for another boxed-up run like at the concluding stages of his race three runs back when Lim's Lightning cooped him up on the fence, Gray shrugged it off.
"He's got the speed to get a nice run from barrier one. It's better than drawing 12," he said.