NRT flights are easy. In Raffles all NRT flights have spacebed, except for the one daily flight via BKK which is 3-class 777 (should be easy to spot). In First all NRT flights have skysuite, except for the aforementioned 777 flight via BKK.

ICN is harder, since you can't know (much) in advance if 747 is SMT or not. If 2 digit flight number then 2-class 777 and spacebed. If 747 I'd just assume non-spacebed and then be pleasantly surprised if get spacebed.