Personally i started out very small only got about 1-2% of my total net worth into crypto before the last bull run happened. That small percentage grew to more than half of my net worth. (thanks to some good investments) Now percentage wise it's back less but i don't adjust because i don't have much to lose since my initial investment is really small.

You should always not risk more than you are willing to lose in the worst case scenario. There is not a ratio you can use to determine how much to allocate into cryptocurrency. It's something personal. Personally i wouldn't put more than 20% of your total net worth into cryptocurrency at most and max 5-10% allocation to a certain cryptocurrency as a way of diversification. Never put all your eggs in one basket.  Long term most of the altcoins will fail along the way. Especially the small cap coin's with no working product. This is not different from most venture capital investing.  It's just a different asset class.