Their moves are sufficiently random that the only way to accurately predict the tops and bottoms is to be privy to they plans of the manipulators. However, we can expect them to keep doing the things they have been doing. They tend to create 1 or 2 small flash crashes each week, varying in size from 15% to 40%. I also suspect that they will invoke another major crash within the next few months.
Even though I cannot predict the tops and bottoms, I believe it is possible to profit from this artificial volativity by placing limit orders to automatically sell on the way up, and then to re-buy on the crashes.
For example, every time the price goes up 5% you could sell 1% of your holdings. As soon as that sell executes, you place a buy order for more coins at a 15% lower price. When that re-buy executes during a small downturn, you re-place the sell order at the higher price. I currently have 21 sell orders placed between $162 and $222, and 11 buy orders between $109 and $139. Every time a sell/buy pair executes, I gain 15% more bitcoins.
I think it's a safe bet that the price will rise again to $250 or more, suffering several flash crashes on the way, and then crash again to less than $100. My system makes money every time I get out and in, and when we crash back to $100 again, I should have considerably more coins than when I started. Also, by selling into rallies and buying into corrections, I help stabilize the price a bit. If more people would adopt this system, we might foil the manipulation scheme entirely.
Your case is different, since you're starting with fiat. I think I would place buy orders ranging from about $100 to perhaps 10% below the current price. As the price rises, keep adding more buys. When we hit the next flash crash, you will certainly hit some of those buys. Immediately place an order to resell those coins at a 25% profit. When those sells execute, use the proceeds to place buys 15% lower.
Or if that's too much work, you could wait for the next major crash. It could take several months, and there's no way to call the exact bottom. But you could wait until 24 hours after a devastating crash, buy in, then gradually sell as the price starts going up again.
The key is to avoid panic buying when the price is high and panic selling after the price drops!
Another reason why we need more people adding liquidity with standing orders.