I tried a pair of "Rossplate" #4 switches and everything--I mean everything--modern and prewar--derailed going through them, so I returned them. It was disappointing as I really wanted #4s to form my crossovers and wanted to buy American and support a forum sponsor, but no such luck.
I ended up trying to modify Supersnap O72 switches to tighten-up the center-rail distance between mainlines when using them for crossovers. It involves cutting and a little soldering, but the end result is worth it as the track distance is almost as tight as it is using #4s, and it didn't affect performance at all. At some point I'll post a thread showing what I did. It has worked really well.
