MELBOURNE, Australia — Getting jet-lagged from all the travel stories?The San Francisco 49ers’ and Los Angeles Rams’ opposite flight/body clock strategies will be discussed long after kickoff Friday morning (Thursday night in the U.S.), and hey, maybe everyone will start flying luxury airliners and turning right around like the Rams. But let’s focus on the game, which would give the 49ers a serious leg up on the Rams. And that brings us to a big mystery.How will the teams adapt to the stadium, the historic Melbourne Cricket Ground, which can fit 100,000 people? Particularly, how will the quarterbacks adapt?The stadium has an oval shape, suitable for cricket and Australian Rules Football but an odd fit for the American version. The 110-meter-long NFL field and goalposts were centered, so fans will be further from the action than in a typical NFL game — and quarterbacks might have a hard time with depth perception and sensing where the sidelines are.49ers quarterback Brock Purdy is known for layering his passes — teammate George Kittle calls him “Beefy five-layer burrito” — and he is curious what the stadium will feel like as well.“Obviously it is a big circle, and the field will be in the middle of that circle,” Purdy said. “Having fans sort of further away compared to right up on the sideline — I don’t know if that’ll be a big impact for me or not, but yeah, that’ll be different.”Locals say the acoustics will be different than a usual NFL game, with delayed amplification from one side of the stadium to the other due to the shape.Purdy nodded and said he needs to “understand the cadence that we have to be on, the noise and everything, handling that, the operation within the huddle, making sure guys can hear things. I’m sure it’s going to get pretty loud at times, which is cool. Those are fun environments to play in.”