There will be a pullback one day but I think it's pointless trying to guess the timing, since you'd be wrong like everyone else is wrong all the time. Just in November many analysts sold waiting for a pull back at 8000, then closing 9000, then at 9500, now at 10.000. Maybe the pullback comes from 15.000 to 10.000, who knows. Secondly, if Bitcoin would crash hard altcoins would go down with it. If you sell BTC now to buy ETH or Dash or whatever, you are selling high but also buying altcoins high.
If you want to buy altcoins today could be a great day compared to Tuesday next week... or really bad. I don't think there's any real way of knowing that.
If you want to sell 50% of your BTC why not for example sell 10% once a week for the next five weeks. Then you would average out the price movements. Each week put it to the alt which hasn't made so big gains. I sold some of my BTC for NEO, which hasn't moved at all now. Also bought IOTA few days ago, but I wouldn't make that trade now when the price has moved up 30%.
I like Exodus too btw, great wallet
I have a kraken account but I've never traded on it.
I like you strategy for selling the 50% over 5weeks. I've always believed in selling 50% to re-invest in AltCoins and holding 50%.
Now I'm gong to add the 5*10% sales method, so far the fees are reasonable.
Thanks for sharing this strategy.