What is your plan to invest with $50.000? all for btc or together with alt coins?
Spreading your investment would be the best. The more you spread the better it is since you will be facing less risk. I would invest around 60% of my money on bitcoins and rest on different alt coins. But do keep that in mind, if bitcoin does well other alt coins tends to do well and but if bitcoin price falls, the other coins also follows the trend.
I used to do, but now I realized that it does not make much sense. Once reduced the price of bitcoin then immediately reduced the price of all altcoins. I trust the bitcoin. So all my supplies are stored in bitcoins.