Signal placement

One item I'd like to get right on my layout is the use and placement of signals. Every country, and sometimes railroad have their own standards, depending on which side of the tracks (in case of double track main) the trains run in each direction, and other factors. I wasn't entirely sure where to put them in the case of US railroads. But after asking around, it turns out that signals , when not on a signal bridge, were usually placed on the right side of the track, a rule that was more strictly enforced until 1985. After that date, the placement can be on the left too, which is sometimes needed to facilitate access for maintenance crews, or geographical challenges etc.  So now my search is on to find a great looking model signals, and I think I have found some great looking ones in the range from BLMA models.