Answer
In practice, real-world latency to a distant hosted server does noticeably slow down large queries, but day-to-day usage remains largely usable at close to normal speed. Local hardware/PC standards and WAN/wireless bandwidth on the China-office side turned out to be bigger practical bottlenecks than China's Great Firewall itself specifically, which was expected to be a major obstacle but in practice wasn't. Both a direct connection to the hosting location and a VPN-routed connection worked without fundamental issues, though large/heavy queries were noticeably slower over the longer distance than typical local-office usage.