What percent of a portfolio do you like to have in speculative long term plays? Why?

I’ve settled on a handful of blue chip stocks (Apple, MS, GOOG, AMZN) and a few safe etfs (VTI, SCHD, BERK.B) but I also have 10% of my total portfolio in Sweetgreen, Riot Blockchain and Bitcoin. I’m curious what percent you all allow yourself for stocks that aren’t quite as safe as the above mentioned and why?