Generator throughput doesn't increase as expected with higher pool count

Testing today has highlighted that attempting to increase Generator's throughput doesn't seem to work as expected.

Increasing the Pool count appears to only increase the actual connections created but that the throughput of requests:

Suspect the issue is threads.each(&:join) which is only executing and waiting for threads for each set of projects sequentially.

Task is to increase throughput, potentially pinned to pool size.