Nice, risky decision but I like it. Even CZ did this kind of thing way back when he started. Much better to hold bitcoins first before you hold some altcoins and now is the right time to buy. At least 20% of your portfolio in bitcoin then 80% to diversify in altcoins that you like. I think you should grab some ETH, RVN and pick new altcoins that are very undervalued.
I think you have it the other way around.
With the way bitcoin dominance is showing it's teeth right now, it may instead be better to invest 80% in bitcoin then leave the reamining 20% to diversify in altcoins with good fundamentals (ETH would be my only pick by the way).