I think anything more than a 1-year contract may be a bad idea. You get to use flex points to level up again after each season and you get the leveling up from XP and training during the season, so you are likely to be more valuable next season and capable of getting a better contract.

Also, it seems to be better to sacrifice a little money in the short term for a promise to start. XPs are based entirely on playing time, and so starting is the best way to build yourself up.