This is just my opinion, but . . .
Unfortunately, the Me-262 is not terribly maneuverable, even with the leading-edge slats. And, yes, you need to keep your speed up or you'll be Mustang fodder; a Mustang (or, for that matter, any other prop-driven fighter) can turn inside of a -262 all day. In WWII, the -262 only got into trouble when it would slow down and try mix it up with the Allied fighters; when it kept it's speed up just used hit-and-run tactics, it was almost unbeatable.
You're gonna have to learn how to use hit-and-run tactics to be successful with the -262; and, yes, you'll only have a second or two to line up your shot loose off a few rounds. Otherwise, if you slow down, you'll get bounced.
Good luck!