I think you should start buying altcoin from today until 20 December. After that date, altcoin will res.
The fork will be on 16th December right? or 20?
The segwit2x fork will happen the 16th of November!
I will wait until the last days before the fork, and then buy some good altcoins such as ETH, LTC. Bitcoin price will continue to go up, just before the fork, so it is an interesting period to buy alts.
but if we see in last case bitcoin price is going up after the segwit, and i think in that time is not a perfect time buy altcoin.