You should never go all in with anything. But if you do not already have a fraction of your portfolio loaded with PM you might better think again right now.
Which is bullshit advice from people who will never make it big. If you understand something better than 99.9% of the population, and it reasonably seems like an absurdly excellent investment then you go full in. If you had done this with BTC, you wouldn't be here sharing bullshit advice. Disclaimer: I am not responsible for people who can't asses what "reasonable" actually is and lose all their money investing in stocks or metals. 
Now tell it to those who bought in the high 4K.
But apart from the risk management (and we're dealing with huge risk imho) if you go all in you can't buy low when the opportunity comes.
