IRL, end speeds are determined by charts and tables in Aircraft Launch Bulletins (ALBs) that are referenced by the shooters. A number of factors, including wind, weight (given to the shooter by the pilot) and environmentals, will determine the parameters for the shooters to set the CSV (capacity selector calve). It’s a bit more complicated than most people realize. For example, a sufficiently asymmetrical loadout could have a more powerful shot than a symmetrical heavier loadout. Regardless, to the OP, 200 knots is pretty high. Don’t think I know of anyone that’s seen it that high.
For more information on catapults, a quick google search yielded this resource.
http://www.navybmr.com/study%20material/14310a/14310A_ch5.pdf