I don’t know whether this link will help, but for what it’s worth, here it is. You know of the 6Q7, but this is 6Q7S, here.
It’s the New Zealand Vintage Radio Society (Inc.). Someone wrote:
A SELF RECTIFYING PENTODE – ROGERS 89RS/6Q7S – OUTPUT PENTODE COMBINED WITH A RECTIFIER
The link to the site’s home page is at the bottom of the list of tubes.