Bus Kunming South Bus to East

I need to go from South Bus Station to East Bus Station early in the morning, leaving around 07:15AM. By metro, it seems that I will need around 45' for transportation. In addition, the 902 bus is servicing this line direct with just 6 stops, possibly the 927 and the K39 too.

Q1: how much time should I budget from South to East by a city bus at that early time (probably no traffic jam)?

Q2: does these city buses have special departure times? If not, how frequent are the departures from East?

Thank you in advance.

Fabrice