Google Cloud advises maintaining storage utilization below 60% for applications sensitive to latency to ensure optimal performance. While using a service account for read operations is a good practice, it does not directly impact latency. HDD storage, being less performant than SSD, is not recommended for latency-sensitive applications. A global load balancer is unnecessary for Bigtable as it inherently distributes operations based on row keys. For more details, refer to Google Cloud's blog on optimizing Bigtable.