Definitely it's going to be tough decisions to make right now, since bitcoin struggles to rise while on top value right now. That's better to take more time to grow your alts before deciding when to sell all of it. By the time, when you fail on that specific decisions you might miss the opportunity to earn those potential profit. So don't rush, analyze what's best for your asset and don't forget to read every updates.
When bitcoin has hard time going up, crypto market doesn't go up that much neither, it just goes up a bit but not a lot, that's why it is not a good way to invest if the only thing you are hoping for is bitcoin not going up a lot but others going up a lot.
I personally believe that altcoins only gain value together when bitcoin does, sure there could be here and there coins that go up during the stagnant period as well but those are rare and we never know which one will do that so picking one is hard choice. That is why I create a portfolio of coins, it has bitcoin and it has altcoins, that way I feel more at ease with myself since if bitcoin goes up altcoins go up as well and if bitcoin stops, there could be some coins that go up if I am lucky and if not it will be there for a while like bitcoin does, it works out in both cases so it is cool to have it like this.