HEL: Great for connections even with less than 1 hour as many have already said.
AY J HEL-BKK//BKK-HEL: Be prepared for backpackers getting upgraded from Y to J (and if you are lucky their friends left behind in Y will come running on and off without any interference from the crew = at least that was my impression).
AY A350 J: I like the seats (same "type" as CX uses I believe) and the cabin is actually very quiet (I like it much better than the B788 tbh)
Just my 2 cents...