Hello,
I AM a UK C++ Systems and software engineer. vast experience.
You need an SDTP compatible commndline client, that can be scheduled to upload files to your SFTP server.
Or, I can write you one - CUSTOM designed and developed - to accept files names, timings(1 per hour) etc, using C++, and you can simply let it be scheduled using Task Scheduler(ideal choice), or run it as a service(not the best choice though) . Can even develop it so that it runs in a loop, and sends a chosen file - based on some choices/rules- every hour?
Cheers
Dinesh