Breakthrough with NetFinder
OK, good news. The latest version of NetFinder seems to know about FTPS, which is what the protocol is called when FTP does SSL/TLS, and does the connecting automatically. This is good news because I now have at least a functioning secure uploader for the time being. Hopefully, Transmit will add this if it's not already in the works now.
Interestingly, I had a hard time figuring out that NetFinder did this because the documentation was pretty darn bad. That is to say, the documentation that came with the program. When you go to their web site, the docs are quite good and complete - which is where you learn that SSL/TLS is tried automatically and if it's successful, a small locked padlock is shown at the upper right corner of the screen. But to figure that out took me a while.
Maybe I'm slow.
In any case, until something better is found, I'll stick with NetFinder and let is go at that. Whew!