Move to Alts in bull market and to Bitcoin in bull market

Crypto market cap fell from USD 100B to USD 65B and bounced back to USD 85B. Even though the market is still down by 15% a friend of mine was able to get 50% return on his investment. His simple rule was to move his assets in Bitcoin when the market was falling and move it to alts when market was rising.
Fundamental analysis shows that most alts have around 95% correlation with bitcoin meaning they go up when bitcoin goes up and they go down when bitcoin goes down. Also they have a beta>2( with Bitcoin as the base currency). What this means that when market is bullish they go at more than twice the pace and when market is going down they fall at more than twice the pace.
In the volatile cryptocurrency market, if you invest in Alts when the market is rising and in bitcoin when the market is falling you will be able to increase your asset value even if the total market cap remains constant.