Guangzhou and Beijing are in the same time zone. Both cities use China Standard Time (CST, UTC+8). When it's noon in Guangzhou, it's also noon in Beijing.
China uses a single time zone across the entire country despite its vast east-west span.
Any time works! Since both cities are in the same time zone, scheduling is never an issue.
Guangzhou is a major southern Chinese city and economic hub. High-speed trains connect Guangzhou to Beijing in about 8 hours.