I think it's best to buy alt now since the next fork date is uncertain. Try to buy altcoins that are good for long term investment and you will definitely gain some profit. due to the delay of the fork, alts are soaring high as of the moment and it will continue to do so over the next days.
Yeah, you might go to bed one day and the bitcoin correction happened overnight, lost a ton of btc/usd value and the alts have already pumped. Now is definitely the time
Alts are pumping now and I think buying it now may hard for you to earn profit but if your goal is really for long term them buy altcoin because it is still cheap and i know all the cryptocurrency will keep on the uptrend for sure in the future. But don't forget to analyze before buying altcoins.