Kurt, if you have your staging set up so that the locomotive always leads, and it's just a case of nudging the loco onto a N/S and properly powered turnout onto the 'yard lead', I would seriously consider recycling the used or new steel rails. It depends on what kind of staging. If it is multiple loops, then your engines will have to rely on clean rails to get around them to face the lead again for later use. However, if you intend to back whole trains down the lead, and then through a turnout onto individual tracks, it is really only the first few inches of rails on those ladders that need power...the rest of the rails holding the non-electrical part of the train can be anything, even stripwood.
What I mean is, use the steel if it can be used without too much hassle. Save the money. If your staging yard design will be such that you want it handy and easy to use, such as with whole trains turning around on multiple parallel loops that need good electrical contact, you might be better off with the N/S rails. If they will back into multiple parallel tangent tracks, use the steel and get used to nudging the locos forward until they catch electrical track.