Am I the only nutcase here with 90% XMR out of total 60BTC worth of cryptos 
You are not simply because soon after BTC will moon Monero will follow.
If you are expert trader, then yes is wize to also hold Bitcoin. If you are not and you would miss the time when BTC moons and buy Monero at that time with all your BTC, then is totally fine to have mainly XMR.
After BTC moons to buy monero is perfectly fine. Right now to own it or buy some is hmmm...not that smart for me.
That si not just fine, but is simply perfect!
But if you are me, that always fails what will happens and have no ideas when BTC orr Monero or any other crypto is at peak or at bottom is just safest to just hold Monero.