lower league? top leagues? best way is just top hop in game, plug it in, get the right players for what you want them to do etc, do the training to get them fluid in it, then you can really test it, one game test isn't conclusive.
i wouldn't overly trust FMC though, i tested a tactic on FMC, it failed, so i tested it on the normal game, some conditions and players and it worked very very well.