When it comes to 9 mm ammunition, there's really two weights (three if you use a suppressor). Fodder in 124-grain bullet weight is NATO-standard, but there's a good argument to be made for the popularity of 115-grain weights, too. Most common practice fodder is available in either of these weights.
SIG Sauer Ammunition offers its excellent V-CROWN projectile in either 115-grain or 124-grain variants (as well as 147-grain for subsonic/suppressed shooting), and we've covered both variants previously. Performance in either bullet weight has been shown to be excellent, so choosing either as a defensive round is a no-brainer.
Practicing with either weight, then, in a less-costly FMJ configuration just makes sense. With similar construction and reliability, it's a pretty fair bet these rounds will handle in a similar manner to the more-costly V-CROWN siblings. So save money at the range, practice more and have confidence in your practice time.