Barcelona is 6 hours behind Hong Kong
Best overlap: 2:00 PM to 6:00 PM in Hong Kong is 8:00 AM to 12:00 PM in Barcelona.
Shoot for 2:00 PM to 6:00 PM in Hong Kong; your Barcelona colleagues will see that as 8:00 AM to 12:00 PM. With 4 hours to play with, a mid-window meeting keeps things balanced for Hong Kong and Barcelona alike. For part of the year the maths changes: Barcelona observes daylight saving, Hong Kong does not, shifting the overlap by an hour.