OK . . .
I think I'm mixing up concepts now. In order for uploads to work better around my NAT and firewall, I thought I'd need to open up port 6346 (and more?) on the firewall . . . then configure the NAT software on my gateway box for "port forwarding." I found a "port mapping" interface (sounded close enough), but adding an entry for a range of ports (6346-6359) hasn't seemed to help.

Still seeing 1000's of pong errors, and nothing in the HTTP requests. I'm not sure what questions I need to ask to get uploading.