I feel like this is a yes and no kind of thing. I read every cradle is a grave and according to research most people choose methods based on what they're familiar with and some people do dangerous things in preparation for killing themselves (get in the right frame of mind kind of thing). So starting by practicing may be a good idea, but there's the chance that you could actually die when you didn't intend to (that's why there's a thread telling you to not test run SN) or you could end up with some kind of disability or brain damage if things go wrong.
Ultimately up to you, but you should consider the risks before you make a decision.