for sure dominance is an important metric to watch, in this current market, it only takes btc dropping a few % and most altcoins will follow, hence, you should only hold a small amount of your portfolio in altcoin, and most in btc, using short positions to cover these small drops
even today bitcoin has fallen sharply, therefore it is now the biggest opportunity to be able to invest most of the money we have against bitcoin and we must also be able to combine a few percent of our money to invest in some potential altcoins