I do not think that "risk management" strategies are sound for BTC. In my book the only way to go is the following:

Invest in BTC an amount you are ready to lose

Don't forget to realize some fiat profits, because unrealized profits = non-existent profits.

Practical example:

Somebody that invested in January this year has already a 50x unrealized profit. Wise thing in my book would be to sell at least 10% of the BTC, cashing in a healthy 5x profit on the initial investment, while keeping 90% of the BTC for the next cycle.

I'm using this strategy myself, with a clear exit plan I tend to follow strictly. I was lucky because I managed to reach x100 in the last run-up (BTC doubled 3 times in 4 weeks), but I would have cashed out even at x50.