I hope I don't get into trouble for bringing this thread back to life, that being said I don't see the point in making a new one for the same thing.
Going with a fantasy approach, because I do not know anything about LED lanterns.
I would use quite a mix of things, sometimes on the same road, I liked the variety that we used to have in North Yorkshire with both lantern types and colours.
For main roads, with SOX I'd rely heavily on Philips MA lanterns and Eleco GR lanterns but also some GEC Z9554 and GEC Z9454. For SON I'd go with the SGS 203, 204, ZX3 with flat glass or a deep bowl, Alpha 8s, Alpha 3s, GEC Z8600 and both versions of the SGS 201, also some traffic visions just to balance things out. I don't know the names of many mercury lanterns but I'd go with the GEC Z8526 and again the Alpha 3s and the old SGS 201s.
For small roads it would be Beta 5, 8, 79, GEC Z8830, Philips MI26, the newer 201 both in SOX and SON, AC 850/888, Revo Dalek and some Eleco Silver Ray Juniors
Forgive my lack of imagination...