In the last bull run in 2017, ETH was exploded within weeks compared to BTC few weeks before the BTC peaked.
If we see nearly anything like that in the next few months, a potential strategy would be to weight in ETH until it reaches 0.12 and shift towards BTC.
So, move from ETH to BTC between 0.12 and 0.15. And after that start cash out BTC as it climbs to the top at the end of the bull run.
If BTC tops between 120k and 250k, ETH will get weeks before the top between 10k and 20k.