With the max-burst doubled, I was seeing better throughput. So I doubled it again and it looks like now I'm seeing around 50mbps
Regarding the block size, I thought the same, however it seemed that anything over 4K was not helping, and I only got better throughput by decreasing it to 1024 and finally 512. Perhaps now that I've increased max-burst, a larger block size wouldn't hurt?
at least this is working now; I wonder if Net::FTP::Throttle should be updated to increase that max-burst? How does stuff like that get done, should I be prompting someone or going at it myself?