That adds pretty noticeable friction over the pre-printed cards, so I think the pre-printed cards make a lot of sense to have.

Note that the game already comes with 25 colored tiles (red / blue / white) which are used to cover the game board, so what you describe could be easily done with the existing game by putting those 25 tiles in a bag, shaking it, and having the spymasters secretly draw all 25 and fill in a grid in the order they draw them, and then proceed with the game as normal from there. I doubt many people would want to bother though.

> that is if the spymasters are not informed of the position for the other team

The spymasters both know all information, so it is indeed even simpler.