I this tactics is very applicable. It will require that you have enough funds to support yourself and put some on stand-by should you find yourself in need to buy more coins.
But the time to buy is also important. You might get some fiat in hand at some point but rushing in to buy is the wrong thing to do. People should keep a track of what new coins are entering the market and which new ICOs are good to buy. Then wait for a dip in the price before they buy. Of course this will take time and it wont happen soon - they might have to wait month before they can find a suitable price to buy.
I always have a spare Fiat, in the amount of 30-50% of the total deposit. this is important, because you can buy in a falling market.
Wow that is huge amount of fiat to hold while still trading. I dont about what others do but you might want to diversify your portfolio before keeping that much for side buys.