I have struggled to snap my trainer .... Too "corrective" and "stable" to do it. Really does not like stalling... so, on the advice of an experienced pilot, do the snaps inverted.

There are some things that your trainer just can not do. Snaps/spins are normally one of them because they rely on wing stalls which trainers are designed to almost eliminate. Trainers also make knife-edges really hard (with Wing dihedral especially), need to carefully control rudder, aileron, and elevator to get it right.

Read your manual again, and get the maximum throws available on your plane. Consider upgrading the engine to make inverted flight easier, and then try to do as much inverted as possible because the wings stall so much better then....

gus