Notice the quotation marks. It's nowhere near a conventional 52 ... more like a 56.5.

There is no rule other than try to keep your position the same (as your road bike, which you don't have) but err on the side of slightly more upright (so your back doesn't explode two laps in). It's not a "I'm on my way out the door to go to work" conversation and unfortunately I'm on my way out the door to go to work.