Depends how aggressive you want to be with it but I would spilt it up into 5 bits then pick 2 coins from the top 25, another 2 from the top 25-200, and then one coin outside that for a pure gamble. That way you diversify and at the same time are in some solid coins too.
Lol, why gamble when you can just take your time to research more on the coin. My advice would rather be to look for the coins in the top 200, try to look for the one that is so less in value; read some little stuff about it and see if it is worth investing and then take a pick on it.
That sounds a lot better than just picking any coin, The fact that they are in the top 200 does not make some of them less of a shit coin.