Hello: I find it harder to get fills if I trade spreads as single order on IB, but if I leg in, the fills are almost instantaneous. One advantage with single order spread is that you get the legs to be margined correctly. The commissions are the same whether I leg in or enter the spread as single order. Any comments? How do you enter spread orders?
I've been entering spreads all at once: verticals, iron condors, iron butterflies without any problems. I simply use the combo feature. Then when I am ready to place the order, I start out placing it half-way between the "bid" and "ask." If it is a sell order, and it isn't filled within a minute or so, I move it a tick closer to the "bid." If it is a buy order, then I move it a tick closer to the "ask." In 2 years, I have never had to hit the "bid" or the "ask;" I was always able to negotiate somewhere in between. By legging in, you will get some slippage, and it usually to your disadvantage. So, take advantage of IB's technology and enter your legs all at once. I trade on GLOBEX; it is, to me, the most friendly-user exchange out there.
Legging in requires that you be able to judge the short term price movement, and if you're good at that, you should be day trading the underlying.
If the B/A spreads are wide, you're better off splitting the bids with a combo order. If the spreads are narrow and you have some ability to catch the short term moves, legging in can get you a good fill. If possible, work the more expensive leg because that's where you're apt to get the better fill and conversely, hurt more if you fill the cheaper leg first and it reverses. Do not attempt legging in unless you have the decisive discipline to pull the trigger quickly.
Combo orders are definately preferable as a long term practice. I am sometimes willing to pay the spread if its a volatile stock and the spread is changing too frequently for a limit order.