This is just a small modification to total's practice romhack that can be found here:

SM (Pinkus) InfoHud+Menu+InputDisplay 1.42 (PAL)
SM (Pinkus) Saving+InfoHud+Menu+InputDisplay 1.42 (PAL)
SM (Pinkus) Saving+InfoHud+Menu+InputDisplay 1.42
SM (Pinkus) Saving+InfoHud+Menu+NoFanfare+InputDisplay 1.42 (Controller 2)
SM (Pinkus) Saving+InfoHud+Menu+NoFanfare+InputDisplay 1.42
SM (Pinkus) SM InfoHud+Menu+NoFanfare+InputDisplay 1.42

Go to Config > RNG Control

Rerandomize: If turned on, your rng/framecounter doesn't "lock in" when you make a save state. For example you can save state right before Phantoon starts moving, and still get different patterns if you keep loading the state.

Phantoon/Botwoon RNG control: Specify the RNG you want to practice