There is a good reason not to run split during a contest, or at least any of the major contests.
Almost inevitably, someone will start CQing on your listening frequency (or someone already was listening on your chosen listening frequency.) He will hear the other stations calling, think they are calling him, calling them and act as QRM on your listening freq. If he is loud enough, he will get spotted, start working stations that come to the freq and you will start hearing stations calling him, but think they are calling you!
So, generally going split not very effective during any of the major contests that have high levels of CQing going on.
That said, years I ago I was K3TN/KP2 and one of the JA CW contests was running and I had a massive pileup of medium strength signals and just had to widen it out. I did the RIT thing, but EU could hear me and even though I was calling CQ JA, many EU stations must have thought that meant Join in Anyone and were essentially jamming my TX freq and slowing things down. So, started sending JA UP to thin that out.
In that regional contest, not that many CQers so it worked fine. Wouldn't do it in one of the major contest, domestic or DX, for the reasons above.
73 John K3TN