If I were choosing three or four assets, then I'd go along the lines of:

Bitcoin 50% - ( ETH / XRP / LTC ) 40% - DOGE 10%

If I had to choose ten cryptos, then:

BTC 1/3rd - ( ETH / XRP / LTC / DOGE ) 2nd third - (( ( newer coins with promise ) + ( some other well establised coin/tokens ) about 50/50 split )) last third