Detuning is overrated in my opinion. I've went all my years without ever detuning.
The only reason I see for detuning is jibbing. I doubt you're jibbing. Learn first and if you find that the board is still very catchy after you get good, then detune it.
If I can learn on a stiff positive camber board, you can learn on a softer magnetraction rocker board.
I agree with Lstar: Just ride as is.