My rule for s/h J in Europe is at least 2 hours, preferably 2,5. Anything under that and you are not likely to get much of a meal and even seat comfort doesn't essentially matter.

I'd like to keep the same rule in Asia and on KA as well. As previously mentioned, does it really matter on a one hour flight which class you are in when the seats and service are reasonable standard in eco anyway?

However, when connecting from a longhaul to Beijing or Shanghai, it makes a difference regarding the seat. Catering is not so important if there was lounge time at HKG but a few glasses of good wine and maybe some fruit or cheese is not bad before heading to sleep at the destination.