Europe time feels the best for me as the matches start at around 9-10pm when it's just dinner/chill time before sleep. This masters, the matches are in the morning and (fortunately) I have a life now so I am yet to watch a match live.
every tournament match always starts at 3pm local time. JP/KR 3pm local is perfect, HOWEVER, this masters tokyo they made it 12pm local time, so American viewers can watch. 3pm JP/KR would be my ideal time