Best region for AppEngine setup for Thailand

I am looking for a least latency and max throughput region for Google AppEngine for users in Thailand. According to Cloud locations closest are Jakarta and Hong Kong. Tried to make sense of an underwater cables map information for my question. Could not put an answer together. What I am thinking is a test setup of 2 GAE applications behind a CloudLoadbalancer and measure user experience (somehow).

However, maybe someone was able to figure it out already? Is it Jakarta or Hong Kong GCP region which is faster to Thailand users?

http://www.gcping.com/

How does this work? Your browser makes HTTP requests to f1-micro instances in each region. The median time between request and response is shown.

The global row uses a Global HTTP Load Balancer to route requests to the nearest healthy instance.

First, just check if both regions have availability for other resources your application will use (like Firestore), so you can have low latency between application and storage as well.

Second, what I used to do in this case, is launching one VM in each region and creating a simple script to make a dozen requests for each VM/region and output its response time. So you can validate if the difference between them is relevant of not.