My SOAP experience last year was unique, but with some scant similarities to the question you are asking. Take it for what it is worth.
Basically, last year (2014-2015) I was in a general surgery prelim spot trying to re-apply for ortho. I didn't match, but I also had a high interest in rads so I went for it in SOAP. Miraculously I got into a great program on the first round and am ecstatic about the result. With a gen surg prelim year almost finished I thought I would apply to an IM prelim year through SOAP just to be that much more well rounded. Long story short, I neither SOAPed into an IM nor a PGY2 prelim surgery spot, which surprisingly exists in decent numbers. Luckily in my case I already had the prelim year taken care of, but was amazed at my not finding another for PGY2 prelim spot to at least occupy the next year with more floor experience.
Another difference in my situation is that I didn't spend much time planning for this scenario...after all, intern year in any high-volume surgery program keeps you thoroughly busy. In your case you're going into it with a plan...I am assuming...which already sets you up for a more favorable outcome. Also, a PGY1 spot is going to be much, much, much more readily available to you on the SOAP list in the event that you have to take that route. Programs all over the country love the "extra labor" provided by having designated prelim spots up for grabs. Hopefully you won't have to worry about that come March. Just apply broadly and don't spend too much time stressing.