You can still leg into a spread. 98% of the time you would leg into a trade from the long side first anyway. You would buy a spread because you think a stock will move in a certain direction. I'm a contrarian so I go against the grain and I understand that my first print is usually not going to be my best. That is why I scale into almost every trade I do. I also scale out of almost every trade.
I don't pretend to know bottoms and tops but I do my homework with charts to figure out ranges, I watch volume and I watch how a stock trades and I get a feel for it (I use my experience). This is how I decide the plays I want to make and I decide where my entry and exit points are. I am NOT a MOMO trader so you will usually see me buying when everyone is selling and selling when everyone is buying. It works for me.