OK, that one I can actually help with. I model '72, the year that the Super C was running strong, the first year of the yellowbonnet paint scheme, and when the FP45's had just been bumped down into intermodal service.
In that year, there was a SOLID mix of both the red "Santa Fe" side trailers and the "blue winged herald" that replace it. You wouldn't see the red "Santa Fe" on anything longer than 40' trailers though; the first 45's were on the more modern scheme.
The pinstripe scheme on diesels lasted well into the mid 70's. Each year you saw proportionately fewer of the red "Santa Fe" trailers as lengths grew and so did the replacement of longer cars to handle them. I don't know what the exact first year was of the winged small herald, I'll say about 1971 but I could be off a year. I know they were around in '72 at least - the 1972 annual report featured a trailer in the lift at Hobart.
About the only thing you really can't get away with is the blue "Santa Fe" sided trailers, those were well into 1979 to early-80's and are pretty much exclusively with the yellowbonnet scheme.
The TrainWorx trailers are very well done, I've collected at least one of each. The one that's really needed though is the Flexi-Van side door NYC scheme, that was more common on the Super C than some of the Santa Fe trailers.
Here's a particularly nice 1975 Super C bicentennial shot with both schemes of trailers in it:
http://www.railpictures.net/viewphoto.php?id=282023&nseq=2