The easiest way to hedge your fortunes is to acquire the same number of XMR as you own BTC, since then it does not matter to you how their mutual exchange rate goes and which technology gains more. Only 0.1% of your BTC need to be diverted to buying XMR to achieve this.
So if you have 21BTC you should have 21 monroj or 2100?
21 XMR. It is actually more % of the total than 21 BTC is (both as per current emission and the long term until ~2050 when XMR overtakes BTC).
So it's not about the monetary sacrifice, it's sacrificing the principle that BTC is infallible and all alts are shit by definition.
I disagree with this if HODLing XMR as a percentage of Bitcoin - I would use either 4 or 5 X BTC Therefore if you have 21 BTC have between 84-105 XMR.