Since I'm in the filestream beta, I'm using that to upload since it seems to handle API limits differently. I have a GCC compute VM. 8GB ram, 2cpus. Then I have a 1.5TB drive, then use a symbolic link to store the GoogleFS cache. Then I basically just download the arq files at a steady rate into the "virtual" drive FileStream makes.
If you run it too fast, it can crash the client. So I'm using 8 transfers. On my local machine I did 64transfers but used 100kb max size to handle all the small files first. Did well for a while. I unlinked Arq from my google drive, and deleted all arq data. So that I'm doing this transfer fresh, then I'll connect when all of them are done.